Jay Wiseman's SM 101 is rapidly becoming a classic, and rightly so. It should be required reading for anyone with the slightest interest in kinky erotic activities. There is a nice balance between safety considerations, both physical and emotional, and creative ideas for pleasing your lover in unusual ways.
As always, Wiseman emphasizes the necessity of consensuality, including how to find others who share your interests, and negotiating your activities. His background as a medical professional gives weight to his discussion of risks and safety precautions. There is also a wide range of ideas for creative play, from just slightly kinky to the truly bizarre.
As the title implies, and as Wisemen points out, this book provides an overview, a very comprehnsive one, but should not be your only source of information on the subject. He provides a helpful glossary and sources for additional information.