Samadhi compiles in one volume the articles written by Donald J. DeGracia, Ph.D. about the practical aspects of yoga, including the mysterious technique of samadhi. Samadhi is the most important method of Patanjali’s Raja Yoga. But it is also the most obscure and cryptic aspect of the Yoga Sutras. The articles in this volume outline Patanjali’s ashtanga yoga methods, describe the ten types of samadhi, discuss sabda, jnana and artha, and present a possible “recipe” for achieving samadhi. Samadhi has no counterpart in our normal, everyday life. It is the most difficult aspect of yoga practice. Mastery of samadhi allows a person voluntary access to any and all possible states of consciousness. Along with his scientific knowledge, DeGracia’s experiences with altered states of consciousness provide a basis to discuss the inner workings of the yoga methods that goes beyond mere intellectual speculation.