Mixed Gas Diving: The Ultimate Challenge for Technical Diving

If you're used to PADI textbooks with glossy photos or summarized explanations about why certain diving rules hold true, you will be slightly overwhelmed. This is an in-depth discussion of the art and science of breathing underwater. As you may know, Tom Mount is the founder and current CEO of IANTD which is slowly surpassing TDI as the predominant certifying body of technical diving. His work is backed by the experience of thousands of dives and the lessons from a few mistakes that he discusses candidly in his book (i.e. on-site DCS treatment, what happens when you dive REALLY deep on air). I have read several books on the subject, to include my training manuals and Mount and Gilliam's work is one of the most comprehensive without getting into advanced physiology. What impressed me the most was the holistic approach they take to diving. They go as far as to discuss the process of aerobic cellular respiration, what it's like to visit a hyperbaric chamber, how to ready a patient on your boat for helicopter rescue and reference yogis and Buddhist monks in proper breathing and relaxation techniques to improve air consumption and reduce CO2 absorption. The information about rebreathers and dive computer technology is a little dated, but their discussion of the development and history of decompression tables (Buhlman, VPM, etc.) that today's modern computers are based on is still relevant. The chapters on gas blending, equipment setup and selecting the best mix for a given depth and duration are readable and offer "plug-in" formulas and practical exercises with an answer key in the back. As with any diving activity, no one should ever undertake a practice they are not trained for, but understanding this book before you receive your training will further your comprehension of topics your instructor may only skim over or avoid discussing.

Mixed Gas Diving looks primarily at the use of exotic gas mixes for diving the extremes. There is a useful chapter on Nitrox for recreational divers, as well as good information on Trimix for those delving a little deeper. The book is comprehensive and explores breathing techniques and the physiologicial effects of different gases. Slightly dated now by new rebreather teechnologies, the book is excellent reading for aspirant Nitrox divers and those already using this gas mix. Required reading for Technical Divers. Chris Cherrington (UK)