Tibet, 4th: Tread Your Own Path (Footprint Tibet Handbook)

Since this is written by a genuine Tibetan scholar, the information provided for the various sites throughout the Tibetan cultural region (ie not just the TAR) is outstanding. Just compare it with Lonely Planet to get a sense of how amateur their descriptions are. However, instead of detailed, well-researched info on cultural sites, LP does provide many more options for eating and sleeping. If you've booked a tour, most of this will be taken care of for you, but there is no chance that your local guide will have as much or as accurate information as provided by Gyurme Dorje. My strategy these days is to take photocopies of the LP for specific areas I'm staying, but I take Footprints Tibet with me.

Also, if you are getting this book just for site information, you should know that there are very few updates between the 3rd and 4th editions. The new one is smaller and lighter, but you can save a few bucks with the older one without losing its benefits.