Well, obviously the guy had a few screws loose, either that or he was an exceptionally successful con artist. Though I didn't know the background information of the author until after I had actually read more than half of the book, and so I don't think my opinion of it was too badly prejudiced by knowing this. Pretty much my opinion is that even if the book were true it was nothing special. It read like it borrowed heavily from Theosophical writings about Tibet, late 19th Century mysticism, very new agey, not really anything I hadn't heard before: tales of telepathy, levitation, astral travel, hypnotism, invisibility, psychometry, geomancy, pretty much the standard fare superhuman abilities attributed to advanced practitioners of Yoga, except it came across more as hearsay, someone repeating what they read elsewhere, but hadn't ever actually experienced themselves. And there's nothing wrong with doing that either, but just don't try to pawn it off as a true autobiographical story, when it clearly is not.
Overall I found the book to be shallow, nothing too extraordinary or original, wasn't even really that entertaining, and this is coming from someone who is absolutely fascinated by all things related to Tibet, yogis, and superhuman abilities, but I would definitely classify this as a work of fiction, and not a very good one either. I'm kind of surprised at how many people liked it. To me, the book would probably appeal most to people interested in mysticism, but who have limited knowledge of it and maybe are hearing about it for the first time here, and so it would probably be amazing to them, not knowing there's nothing original here, and everything in this book could definitely have been written by someone who has never been to Tibet. Kind of like Jules Verne's Journey to the Center of the Earth, except that's a better book.
Cool book cover though. It also helped that it was a fairly short and easy read. So it wasn't a complete waste of time. I gave it two out of five stars. One good thing that came out of it was it rekindled my interest in Tibet, and in learning more about its history, so I've already requested a few books on the subject, and look forward to reading more about it soon. And will also read one more book by this author, because I had already requested it weeks ago and it's on the way, so I might as well try to read it, and maybe I'll share a few thoughts about it when I get the chance.