Roy Walford's 1994 book co-authored by daughter, Lisa.
"The Anti-Aging Plan: Strategies and Recipes for Extending Your Healthy Years is the first book by Roy L. Walford, M.D. since he completed his stint as physician of the Biosphere 2 team, and includes the startling results of that experience: After only six months, average weight decreased by 26 pounds in men, by 15 pounds in women, and cholesterol levels dropped by 68 points, from average levels of 191 to 123. Blood pressure levels dropped from an average of 110/75 to 90/58 after only three months! No other sustainable diet has ever been shown to produce changes as dramatic as these. "
This is the book I started with upon starting the program and is an excellent intro to human CR. However, 2000's Beyond the 120 Year Diet : How to Double Your Vital Years is Walford's best -- and most updated -- book.