This book was an intense page-turner, every chapter detailed the dangerous and often surprising measures the US Navy took to spy on the Soviet Union. The early attempts with diesel subs soon exposed their limitations but with Admiral Rickover's wonder sub Nautilus would emerge the perfect espionage platform. Follow the true-life adventures of the USS Halibut as it searches for Soviet sub wreckage, the deadly cat and mouse game that occurred between US and Soviet subs that often led to dangerous collisions and the deadly secret that may have killed the crew of the USS Scorpion. Packed with numerous interviews and testimonies from both US and former Soviet naval crewman, the novel truly opens up the world of submarine warfare and the measures taken win the undersea Cold War. A great novel for anyone who is a fan of Tom Clancy style adventures; this is the real life Hunt For Red October. Be sure you watch the excellent History Channel program based on the book.