The biophysics of diving and decompression in the human body are complex. The average individual experiences atmospheric pressure swings of 3% at sea level and over 20% at altitudes greater than a mile. Divers and their equipment can experience compressions and decompressions in orders of greater magnitude than pressures outside water, all within considerably shorter time spans. The understanding of the mechanics behind diving is based on absolute pressure and pressure changes. While these mechanics are readily quantified in physics, chemistry, and engineering applications, the physiological and medical aspects of pressure changes in living systems need to be understood clearly to assess the safety of routine divers. This monograph is a compilation of a body of knowledge on biophysics, gas transport, bubble studies and physiological models used for diving and hyperbaric applications. Information in the monograph is divided into three parts that cover biophysics and models, data correlation and validation approaches and practical applications, respectively. The book is a useful resource for researchers and maritime professionals who wish to understand the biophysics behind underwater diving and decompression for the purpose of maritime operations as well as diving simulation applications.