The ordeal of the ''K-219'' took place at the very height of the cold war.
Much of its story is still shrouded in secrecy. Operations involving American submarines are simply not discussed by the United States Navy.
Ironically, it proved easier to obtain information from the Russians. Events portrayed in this book reflect that difference. Acts taken by, conversations held between, even the private thoughts of the crew of the ''K-219'' are taken directly from their testimony or from the submarine's log.
Actions inside and maneuvers made by the American sub present at ''K-219s ordeal were reconstructed from Russian observations, American reports, interviews with many American naval officers and experts, and the author's long experience in naval affairs. Conversations and commands portrayed in the book may not be the actual words spoken, the commands sent, or the orders received.
Like any intelligence analysis, the authors had to reconstruct this story from multiple sources. Sometimes they disagreed on the details. Their substance, however, is true.