Exciting narrative of a submarine disaster and ultimate rescue of most of the crew in 1939 off Portsmouth NH. The book also is an insightful telling of the career of Swede Momsen as he struggled to experiment and find ways to bring people back from the deep; resulting in safety devices mandatory on subs to this day. Not familiar with submarine layout, I did find the descriptions of the various rooms within the submarine hard to follow, and a line drawing would certainly have clarified that for the reader. A couple of little geographic nitpicks from a local, too: The Portsmouth Naval Shipyard is not in Portsmouth NH, it is really in Kittery, ME ... and Campobello Island is not in Maine, it is in nearby New Brunswick, Canada. But those are minor points. The book is excellent and kept me reading long after bedtime.