Sheck's book delves deep into what drives people to pursue an activity that most "sane" people shudder even to think about. Written by the one individual who was recognized as the finest cave diver in the world, he has both the experience and breadth of knowledge to write a truly superlative text on cave diving. Included in his narrative is a history of cave diving, related by one who helped set much of it. During his life, Sheck helped set the standards for safe cave diving, and was responsible for pushing many of the limits of the sport. In fact, many of those barriers he broke still stand as records or significant milestones. With the publication of this book, Sheck, even after his unfortuanate, untimely death, continues to contribute to an endeavor that epitomizes the nature of man... the curiosity, drive, and willingness to explore the environment in which he lives, even though the price of that knowledge may be death. If you are interested in caves, diving, or just man's willingness to explore, this book is a "must read."