Adventure books, fiction or nonfiction, have always attracted me. Sometimes while reading them, I think--I could do that, or more often, no way would I try that. This book seemed mostly credible. The main character, a former Navy doctor, takes on a short term assignment to figure out why members of a deeply submerged crew are experiencing strange symptoms. The project is different than it seems, and there is probably some people on board who wish to sabotage it. Whom should he trust? Will he get out of it alive?