Biologist and technical diver Dr. Klaus M. Stiefel explains some exciting new insights into the workings of the human brain for the interested layperson. Topics include novel results on the mechanism causing the dreaded which can distort a diver's senses and the brain-mechanisms of controlling breathing and breath hold during freediving (apnea diving). The book also discusses new scientific results about the genetic adaptation of Southeast Asia's "sea gypsies" (the Bajao tribe) to extended breath hold diving.