John Lilly invented the floatation tank. In chapters 1-3 he explains the how, why and possibilities. Useful. Unfortunately, E.J. Gold contributed chapters 4-8. Gold tells everyone at a floatation tank workshop "do not wee-wee in the tank". Right.Gold also contributed ink drawings throughout the book that are just plain weird, hard to take and disturbed. Skip this book and find floatation tank information elsewhere