The book 'Lone Survivor' is the story of Marcus Luttrell, a Navy SEAL who was the only member of his team to survive a mission in Afghanistan. The book provides a first-hand account of the training and skills that Navy SEALs must master, as well as the mental and emotional strength it takes to complete such a difficult and dangerous job. In addition, the book provides insight into the brotherhood that exists among the SEALs, and the lengths to which they will go to protect and support one another.