This book constitutes a brief overview of the development of one type of submarine over a period of 50 years. Much of the history of these boats is shrouded in secrecy, and consists of thousands of men spending endless days on patrol, preserving the peace by their presence. In the main, they were and continue to be successful in this mission. Here is not a story of heroic battles where ships are torpedoed and aircraft shot down, but rather a story of engineering trade-offs and technological advances. The heroics are in the work itself.