Discover Crystals: A Complete Guide To Working With Crystals, by Ursula Markham. Part of the Discover Series, pub. Aquarian 1991 (old of print but second hand copies available)
This series is generally a very good start. Information in this book is concise and comprehensive, includes section on dowsing and how to grow your crystals. I have also read the Astral Projection and Runes books, which are other books by the Discover series.
