I've always been suspicious of a Western tendency to worship at the feet of the Dalai Lama, condemn China for its invasion and subsequent treatment of Tibetan culture, and call (no doubt hopelessly) for the restoration of the hereditary theocracy. The current Dalai Lama may be a very nice bloke, but when he dies a group of religious courtiers would get to rule for the next couple of decades, and then who's to say what the next one would be like?
It is difficult, however, to get a decent handle on pre-Chinese Tibet, since the whole topic is so tied up with active politics.
So I've found my reading group's current text, Alexandra David-Neel's My Journey to Lhasa, very interesting.
She was apparently the first foreign woman to reach Lhasa, officially closed to women, which she achieved by disguising herself as a poor pilgrim. Now she is very much an imperious, sometimes arrogant, woman of her own Western culture, but I found the following account particularly interesting....
"The poor peasants, to whom my apparent poverty and my beggarly attire gave confidence, described their distress in that country where the soil does not produce every year enough grain to pay the pax in kind.
To leave the country, to look for better land or less exacting lords, is not permitted. A few ventured the flight and established themselves in neighbouring provinces. Having been discovered, they were taken away from the new home they had created and led back to Tashi Tse, where they were beaten and heavily fined.
Now many who had thought to imitate them, too frightened by the fate of their friends, remain, resigned, all energy destroyed, growing poorer each year, expecting no deliverance in this life. Others looked towards China. 'We were not ill-treated in this way when the Chinese were the masters,' they said. 'Will they come back? Maybe ... but when ... We may dies before.'"
Food for thought.
(Reference from a 1940 Penguin, first published 1927. No translator's name given.)
Here's her "official website" (a lot of it in French) and a short bibliography.