The quintessential book on Shambhala/Shangri-la, although fiction, is Lost Horizon. Most people who know anything about Shambhala/Shangri-la have garnered it in some way through or from Lost Horizon, either the book written by James Hilton and published in 1933 or the classic black and white movie of the same name released in 1937. Although the story is mythical in context as Hilton presents it, for a person that had never been to Tibet --- through the novel's main character Hugh Conway --- he describes the hidden Himalayan valley he calls 'Valley of the Blue Moon' wherein Shangri-la resides thus:
"Conway was glad to find that the valley was not to be 'out of bounds,' though the difficulties of the descent made unescorted visits impossible. In company with Chang they all spent a whole day inspecting the green floor that was so pleasantly visible from the cliff edge, and to Conway, at any rate, the trip was of absorbing interest. They traveled in bamboo sedan chairs, swinging perilously over precipices while their bearers in front and to the rear picked a way nonchalantly down the steep track. It was not a route for the squeamish, but when at last they reached the lower levels of forest and foothill the supreme good fortune of the lamasery was everywhere to be realized. For the valley was nothing less than an enclosed paradise of amazing fertility, in which the vertical difference of a few thousand feet spanned the whole gulf between temperate and tropical. Crops of unusual diversity grew in profusion and contiguity, with not an inch of ground untended. The whole cultivated area stretched for perhaps a dozen miles, varying in width from one to five, and though narrow, it had the luck to take sunlight at the hottest part of the day. The atmosphere, indeed, was pleasantly warm even out of the sun, though the little rivulets that watered the soil were ice-cold from the snows. Conway felt again, as he gazed up at the stupendous mountain wall, that there was a superb and exquisite peril in the scene; but for some chance-placed barrier, the whole valley would clearly have been a lake, nourished continually from the glacial heights around it. Instead of which, a few streams dribbled through to fill reservoirs and irrigate fields and plantations with a disciplined conscientiousness worthy of a sanitary engineer. The whole design was almost uncannily fortunate, so long as the structure of the frame remained unmoved by earthquake or landslide."(source)
Now, read what the deeply spiritual holy man, Lama Anagarika Govinda (1898-1985), who lived and traveled extensively in India and Tibet most of his adult life has to say. In his book The Way of the White Clouds (1966), Part 4, Return to Western Tibet, Chapter 45, speaking from his own personal experiences of the many unknown, hidden and mysterious places and canyons of Tibet, Govinda writes:
"When James Hilton in his famous novel, The Lost Horizon described the `Valley of the Blue Moon,' he was not so far from reality as he himself or his readers might have thought. There was a time when in the far-off canyons of Western Tibet there was many a hidden `Valley of the Blue Moon' where thousands of feet below the surface of the surrounding highlands, accessible only through some narrow rock-clefts and gorges, known only to the local inhabitants, there were flower-bedecked gardens, surrounded by trees and fields of golden wheat and fertile pastures, through which, like silver veins, flowed the water of crystal-clear mountain streams. There were lofty temples, monasteries and castles, rising from the surrounding rock-pinnacles, and thousands of neatly carved cave-dwellings, in which people lived comfortably, without encroaching on the valuable, fertile soil. They lived in a climate of eternal sunshine, protected from the cold winds of the highlands and from the ambitions and the restlessness of the outer world."(source)
If you set aside James Hilton's aforementioned fiction book Lost Horizon and Govindia's more general Tibetan book, then Edwin Bernbaum, PhD, by virtue of his most well-received and influential non-fiction book, THE WAY TO SHAMBHALA: A Search for the Mythical Kingdom Beyond the Himalayas (1980) rises to the top. Although Bernbaum is highly recognized in any number of areas, he is considered in most circles as the avowed expert and go to guy on Shambhala, AKA Gyanganj or Shangri-la. Bernbaum's book is pretty much de rigueur on the subject in the English speaking world. Any serious internet search using one, two, or all three of the names the mysterious hermitage is generally known by, Bernbaum's name invariably comes up, usually in relation to his book. So too, no respected work on Shambhala, and some even not so respected, that doesn't include mention of Bernbaum's either in the main body of their text or footnoted usually can't be taken seriously.
Interestingly enough, as widely known and as widely quoted Bernbaum is in relation to the subject, he himself, since the early years of the publication of his Shambhala tome, personally seems to have had a tendency to shy away from the subject, putting more and more distance between himself and Shambhala as he can.
The strength of Bernbaum's Shambhala related expertise however, stems from the enthusiasm promulgated from and during those early learning stages, that is, his years as a volunteer in the Peace Corps serving in Nepal. Although as near as I can tell, in that he and I were both in the Peace Corps and we seemed to have served within a few years of each other, our experiences were worlds apart, yet still similar in some areas.
I served in the sultry sea level tropics of the Caribbean --- where I ended up apprenticed under a Jamaican man of spells called an Obeah --- while Bernbaum served under almost totally opposite climatic and cultural conditions found in the high altitude and mountains of Nepal. From my own experience unfolding as it did between the Obeahman and myself while I was a volunteer, I can vouch that any number of doors or opportunities could have easily opened or been made available to Bernbaum during his service, adding, at least for me, a depth of credence to what he has to say that might have otherwise gone unnoticed. 
Where a few years and thousands of miles may have separated Bernbaum and me as volunteers in the Peace Corps and his experience in Nepal, my own experience described as having transpired at the monastery high along the Qinghai-Tibet plateau did however, happen long before either of us joined the Peace Corps and well before Bernbaum ever went to Nepal. Nowadays however, tied to Shambhala as Bernbaum is, it is not unusual to find the following legend, although not by him, associated fully hand-in-hand with what he has to say. The written English version of the legend as it appears in the west and presented below, is attributed (here) to anthropologist and former college professor Helen Valborg from a chapter of her book titled Symbols of the Eternal Doctrine: From Shamballa to Paradise (2006):
"Wandering in a hidden valley beneath the snow-wrapped shoulders of the Dhaulagiri massif, a lone hunter from the region of Dolpo hearkened to the echo of lamas chanting and the beating of drums. Tibetans tell the story of how this simple transient followed the sound of the music towards its source, which brought him to a doorway in a great cliff. Passing through it, he found himself in a beautiful valley adorned with verdant rice fields, villages and a gracious monastery. The people who lived in this valley were peaceful and happy, and they extended to the hunter a warm welcome, urging him to stay. He was delighted with their blissful existence but soon became anxious to go back to his own family and bring them to enjoy the beautiful valley. The residents there warned him that he would not be able to find the way back, but he was determined to leave. As he made his way out through the cliff door, he took the precaution of hanging his gun and his shoes beside the entrance to mark it. Confidently he went to fetch his wife and children, but when he returned to the hidden valley, he found the gun and shoes hanging in the middle of a blank rock wall."(source)
If you clicked the image of Bernbaum's book, above, it would have linked you through to a very well written and informative review of his book that appeared in The Daily Lama. In the review the following is found:
"Although there are differing opinions as to where Shambhala actually is, the lamas all agree that it is a place of majestic beauty. They are more specific about the kingdom itself and give a remarkably clear and detailed picture of it. According to their descriptions, a great ring of snow mountains glistening with ice completely surrounds Shambhala and keeps out all those not fit to enter. The texts imply that one can cross the snow mountains only by flying over them, but the lamas point out that this must be done through spiritual powers and not by material means."
Most who know of or speak of Shambhala agree that to reach the mystic hermitage requires spiritual powers and not material means. Notice how the reviewer writes of the commonly regarded view of the need to 'fly' to do so --- which is in contrast to the Tibetan legend cited above and my own experience. However, the flying aspect or the need to do so is not to be discounted. See The Zen-man Flies. See also:
THE CODE MAKER, THE ZEN MAKER
SHANGRI-LA, SHAMBHALA, GYANGANJ, BUDDHISM AND ZEN
JAMES HILTON AND SHANGRI-LA
EARLY SHAMBHALA RESEARCHERS: 987 AD - 1820 AD
THE CLASSIC 1937 BLACK AND WHITE MOVIE LOST
HORIZON IS BASED ON THE SHAMBHALA LEGEND.
PEACE CORPS ZEN
SHOW ME A PEACE CORPS VOLUNTEER
Lost Horizon and/or The Way To Shambhala notwithstanding, there is supposedly another publication out there that is said over-and-over to be the MOST comprehensive account of Gyanganj ever written. That book was said to have been composed by a venerated Indian holy man by the name of Gopinath Kaviraj (d. 1976).
Somewhat before 2002 and several years afterwards I had a website on the net that presented a brief but thorough background summery on Kaviraj. That website, like many I had on free servers, vanished into cyber space a long time ago. So said, I never got around to bringing the page back to life under a new banner. However, on-and-off over the years I have found several replicated pages of the same summery around the net, albeit without any credit back to me regarding authorship.(see)
Not to play down Kaviraj's stature or accomplishments as a revered holy man on a larger scale, for me the only real interest I had about him personally, and the reason I created my own bio page on him, stemmed from his supposedly first hand, or more clearly, near first hand knowledge of Gyanganj. Over-and-over it had been reported --- and still is --- that at one time he wrote a book titled Siddhabhoomi Gyanganj, which was supposedly translated from the original Bengali into Hindi and published through the auspices of Bharatiya Vidya Prakashan. It has been reported that Kaviraj's main source of information was his own guru, Swami Vishudhananda, a contemporary of fellow Benares Siddhi master Trailanga Swami and Swami Totapuri, the three said to have had lifespans of several hundred years or more, with Vishudhananda himself having had personal experiences in Gyanganj. Through that specific direct connection Kaviraj's book is said to have been written.
For years I have been trying to get a copy of Kaviraj's book in order to personally get first hand information on what he actually wrote rather than through third party thrice removed sources. I am yet to even see a first edition or any edition, let alone read one. A search of Bharatiya Vidya Prakashan's official published offerings, although it lists many books attributed to Kaviraj's authorship, none of them carry the title Siddhabhoomi Gyanganj specifically. The closest is titled Siddhbhumigyanganj by the same publisher, and, in that it is written by Kaviraj in Hindi it may well be the same book (notice the Hindi or possible phonetic spelling "bhoomi" in the original title compared to the Sanskrit word "bhumi" in second title). It does, however, carry a publishing date of 2010, making it late into the game and making it, if it is the same book, a reprint.
There is another book by Kaviraj, that has been translated into English --- although not as comprehensive as the above mentioned book, but covering much of the same subject matter and material --- readily available, titled JNANAGANJA: A Space For Timeless Divinity.
It just seems odd when it is all said and done someone who's work is as well respected, for example, as Victoria Dmitrieva, as found in her partial fulfillment for her Masters Degree in Religious Studies from McGill University (1997) --- that circulates exclusively around Shambhala --- in her bibliography, the translator that she is, doesn't cite Kaviraj's book (i.e., the original Bengali version). Her bibliography is five pages long with over 70 listings, all in reference to Shambhala, Shangri-la, and/or Gyanganj. In her bibliography she cites, for example, the contemporary albeit now deceased, Chogyam Trungpa Rinpoche and his book SHAMBHALA: The Sacred Path of the Warrior, although very good, is not necessarily the strongest tome on Shambhala ever written, as one of her references. However, not a word on Kaviraj --- whose book is supposedly the most comprehensive account of Gyanganj ever written.
GOPINATH KAVIRAJ PART I
PART II---------------PART III
MISTAKEN FOREIGN MYTHS ABOUT SHAMBHALA
As for Peace Corps volunteers, of which I was one, while it is true most of the weight falls on the individual, that is, their personality, demeanor, and approach, et al, once trust is established, generally speaking, even though they are 'outsiders' there is usually greater acceptance and have better access to the locals and surrounding communities than the typical passing through trekker, tourist, or itinerant 'hippie-type' hanger-on.(see) Although nowhere does Bernbaum intimate he ever actually stepped foot in, went to, visited, or saw Shambhala, the overall thesis of his book seems to indicate he forged a strong reciprocal mutual trust between himself and those he interacted with, some of who may have done just that (i.e., visited Shambhala). Why in Bernbaum's case that veil wasn't pierced affords an answer I am not privy to, but there are reasons. In either case he seems to have avoided, clouded, or circumnavigated around the issue in his book. Personally, without putting words into his mouth, I think there is more to his story than he has been willing to present.
As for establishing trust, as with Peace Corps volunteers and locals, it is built in many ways. For example, in my case, one day while I was in the Peace Corps, a young girl living in the small village close to where I lived was hit by a car on the mountain road. The vehicle took off leaving her injured and unconscious laying facedown in the dirt. The girl's parents, like most of the locals, were poor. Being poor they were not able to afford a regular doctor, so instead they opted for a less expensive, local solution. That solution included me, because I knew the parents, and another village member making a sling hammock suspended between two poles placed on our shoulders and carrying her slung front-to-back between us on what turned out to be an all day rugged journey high into the mountains of Jamaica. Our goal, to find a nearly hermit man of spells called an Obeah.
Because of those endeavors, that is, assisting an injured young villager and her family, who otherwise would have been unable to return her to health, there was established a different sort of relationship between the Obeah and I that otherwise may have not transpired.
Many months later I contracted Dengue Fever from some errant mosquito. I was laying in bed in pools of sweat, delirious with a high fever, not eating, and basically unable to move. A villager happened by and reported how sick I was to a village elder. He inturn passed word to the Obeah. Under NO circumstances had the Obeah ever been known to leave his mountain lair, everyone in need of his services ALWAYS had to go to him no matter how serious the situation. However, much to the suprise of everyone in the village and others for miles and miles around, within a few hours of hearing of my condition the Obeahman showed up on the veranda. He would not enter my house for a number of reasons, some having spiritual meaning to the Obeah, some otherwise, such as me being a white man. He did, however, remove a variety of items and herbs from his medicine bag and perform a set of rituals that included spreading sand and ashes in a circle, casting bones into the circle, sitting Buddha-like doing some chanting and using smoke that waifted throughout the house.
The day after the Obeah departed and following a night of heavy wind and rain, I was conscious but racked with pain. For the first time in days I was able to move and hobbled out onto the veranda. Barely able to stay upright I stood before the shaman's circle, and despite the severity of the storm of the night before, the circle was still in place just as it had been left by the man of spells. An ever so slight breeze came up and spread across the veranda floor twisting itself into a small dust-devil-like vortex encompassing my bare feet and legs with the ash and sand of the circle. As the twisting breeze climbed my body the pain dissipated eventually disappearing altogether along with the wind.(source)
THE PEACE CORPS VOLUNTEER
AND THE ASIAN WARLORD
AN EMAIL TO THE WANDERLING
A FORMER PEACE CORPS VOLUNTEER QUERIES
THE WANDERLING ABOUT HIS TIME IN JAMAICA
Please go to Footnote 
PREMONITION TO THE PEACE CORPS:
In Doing Hard Time In A Zen Monastery I write about how I was brought before the presence of a very old and ancient man of Zen who had come down out of the even more rarified atmosphere of the high Himalaya mountains and asked to see the monk who was said to be under the protection of the Lord Buddha. Because of respect paid him by all, plus the serenity he seemed to abide in, it was clear the old man was Enlightened. After meeting him, there was something about him that would just not let go and it continued to gnaw at me for the longest time. Months went by. Finally, when the weather turned such that I could, I sought out the old man, visiting him at what was not much more than a stone-pile hut along the edge of a stream.
In Zen Monastery, other than saying that I went to see the old man I do not elaborate on any travails I may have encountered getting to his hut or on my return. In Hope Savage I relate to the readers basically the same story except that I interject more ordeal-like aspects encountered during my journey. To wit:
"Going to and from his abode was a very arduous several day trek, much of it through rugged and steep very high altitude territory. A good portion of the trail followed along side a series of streams that may or may not have been the same one, that was sometimes rushing and other times placid depending on the steepness or flatness of the terrain."
Even though the Zen-man and I were not able to communicate verbally in the standard way because neither of us had command of each other's languages, he as a man of Zen as were my leanings, for all practical purposes the two of us were quite comfortable in how we had established a working relationship of understanding between us. However, not operating at his level, for me there remained many more unanswered questions than answered ones.
In the mountains generally it was out-and-out cold, but in the rarified higher elevation where we were it was even more so. Even so, considering the usual outside nighttime temperature drop, with the tiny almost candle-like fire in his stone hut, it was typically bearable.
The day before I was to leave we spent a good part of the daylight hours scrounging around for burnable material. To me the amount we gathered seemed much more than would otherwise be necessary, but what I found even more odd was that we left nearly half or more of what we collected neatly stacked at the long abandoned stone hut he had shown me a few days before.
After returning to his hut and leaving the rest of the material we gathered, we put a little food, a few utensils and tea in a shoulder bag then went back to the abandoned hut before sundown for reasons to me unclear. After arrival we ate, then in the declining if not all but gone sunlight he searched around and found what at one time appeared to have been a fire pit. Following his lead the two of us put together a fairly good sized, considering what his fires were usually like, almost pyre-like pile of combustibles. With the sunlight gone and total darkness having fully encroached on us by the time we finished the Zen-man lit the fire.
We sat in meditation facing each other across the fire on an east-west axis with me facing east toward what would eventually be the location of the rising sun. At some point into our meditation, and non-Siddhi related, there was somehow a coalescing of our mind processes forming a single mental entity where we both able to understand each other's thoughts.
In the thoughts he was willing to share he revealed he had spent many, many years as a young man on the other side of time in Gyanganj, but one day he passed through the monastery portals to the outside world and when he did, he became an old man. Before the full abilities of the thought exchange phenomenon faded into oblivion I brought up, considering his age, about the arduous trip back and forth through the mountains to and from the monastery for example, and how, even for me in my somewhat comparable youth and the physical condition that accompanies it, how difficult it was. What I garnered as a response was that I travel my way and he travels his way.
The next morning the Zen-man was gone. So too, neither was he to be found when I returned to his hut, although I did find a rolled up piece of cloth tied to the strap of my shoulder bag. Marked on the cloth, most likely done so from the burnt end of a wooden stick, were four Chinese cuneiform characters, one in each corner and, filling most of the center, the outline of some sort of a shape I didn't recognize.
When the four Chinese characters were deciphered they turned out to mean nothing more than colors: red, yellow, green and black. The outlined shape in the center remained a mystery and meant nothing to anybody who saw it. The mystery however, was solved on its own some 15 years later, a period of time that found me living in the Caribbean island country of Jamaica, and was solved almost on the first day I arrived for what turned out to be a two year stay. So too was answered, before I left the island, my comment regarding how arduous the trip back and forth through the mountains was and his response that I travel my way and he travels his way.
The first part was answered right after leaving the airport to the train station. Almost immediately I saw a giant map of Jamaica and instantly I recognized the shape of the island as being the exact same shape the Zen-man drew on the cloth some 15 years before, an island or place he probably never saw or heard of in his life. Secondly, on my train ride through the cities and hinterland I saw all over, again and again the dominant colors of red, yellow, green and black in the graffiti adopted from the country of Africa and used by the Rastafarians in the graffiti that was plastered all over on almost every available open space. Those two eye-openers along with my experience high in the mountains with a Jamaican man of spells called an Obeah led to the meaning behind how the Zen-man traveled those so many years earlier as found in the following:
THE WANDERLING'S JOURNEY
I have not been able to locate an online version of the bibliography of all the sources used in Bernbaum's book. If you are interested in further research and do not have a copy of Bernbaum's book at your disposal which has within its contents, as he calls it, a selective bibliography, as an option, a fairly comprehensive list of relevant sources can be found by going to either the Victoria Dmitrieva link in this paragraph or the link following this paragraph for a PDF version of THE LEGEND OF SHAMBHALA IN EASTERN AND WESTERN INTERPRETATIONS, the thesis written by Victoria Dmitrieva as a partial fulfillment for her Masters Degree in Religious Studies from McGill University (1997). At the very end of her thesis there is a bibliography of the research sources she used five pages long with over 70 listings, all in reference to Shambhala, Shangri-la, and/or Gyanganj.
THE LEGEND OF SHAMBHALA IN EASTERN AND WESTERN INTERPRETATIONS
Someone brought to my attention Bhagavan Das asking does he not fill the bill not only in books and on the internet, but what I myself have written about him (i.e., itinerant 'hippie-type')? I have to admit there are many aspects of Bhagavan Das that does seem to fall into being an exception to my general rule category. However, to his credit, although Bhagavan Das may have had all the outward appearance of a hippie-type he was far from itinerant having been in India at least six years and had an uncanny ability to assimilate into his surroundings.
The following is what Dr. Richard Alpert wrote about Bhagavan Das in his book 'Be Here Now' after having traveled throughout India with him for months and months:
"I didn't know anything about his life. He didn't know anything about my life. He wasn't the least bit interested in all of the extraordinary dramas that I had collected ... He was the first person I couldn't seduce into being interested in all this. He just didn't care.
"And yet, I never felt so profound an intimacy with another being. It was as if he were inside of my heart. And what started to blow my mind was that everywhere we went, he was at home.
"If we went to a Thereavaden Buddhist monastery, he would be welcomed and suddenly he would be called Dharma Sara, a Southern Buddhist name, and some piece of clothing he wore, I suddenly saw was also worn by all the other monks and I realized that he was an initiate in that scene and they'd welcome him and he'd be in the inner temple and he knew all the chants and he was doing them.
"We'd come across some Shavites, followers of Shiva, or some of the Swamis, and I suddenly realized that he was one of them. On his forehead would be the appropriate tilik, or mark, and he would be doing their chanting.
"We'd meet Kargyupa lamas from Tibet and they would all welcome him as a brother, and he knew all their stuff. He had been in India for five years, and he was so high that everybody just welcomed him, feeling 'he's obviously one of us'."
KERMIT MICHAEL RIGGS