My husband bought me "Oh My Dog" by Beth Ostrosky Stern for my birthday one year. I really enjoyed the information in it.
"The Shih Tzu Handbook" by Barron's is a very good starter book for anyone interested in purchasing a Shih Tzu or newly owns a Shih Tzu.
"The Genius of Dogs" by Brian Hare & Vanessa Woods explains the inner mind of the dog and how much they really do understand from us humans.
Anyone who is interested in learning about the Shih Tzu breed needs to have "The Complete Shih Tzu" by Victor Joris in their collection. This book tells the history of the Shih Tzu in detail.