This book focuses on physics and associated mathematical relationships. Basic principles are first presented, and then practical applications and results are detailed. The intent here is to present a working view of physical phase mechanics, then followed by application to decompression theory in diving. It is directed toward the diver and reader with a basic understanding of decompression. Basically the mechanics of tissue gas exchange, bubbles and nucleation, supersaturation, perfusion and diffusion, and related mechanisms are discussed. The targeted audience is especially the doctor or physiologist, physicist, chemist, mathematician, engineer or biologist by training and also the commercial diver, technical diver, instructor, hyperbaric technician, underwater researcher, looking for greater detail. Bruce Wienke is a Program Manager in the Nuclear Weapons Technology/Simulation and Computing Office at LANL. He contributes to decompression workshops, symposia, educational publications, and technical periodicals. He is the author of seven books, and over 200 technical journal articles. Units and Equivalences Part 1: Material Dynamics Part 2: Transport and Flow Kinetics Part 3: Phase and Bubble Dynamics Part 4: Critical Tensions and Phase Volumes Part 5: Mixed Gases and Decompression Part 6: Operational Diving Part 7: Computing and Decompression Algorithms Epilogue Appendix A: Basic Physics Appendix B: Statistics and Data Correlation Appendix C: Earth Geosphere Appendix D: RGBM Recreational Air and Nitrox Tables Appendix E: RGBM Technical Mixed Gas Decompression Tables Appendix F: Table, Meter and Profile Risk Analysis References.