Submarines lurk unseen beneath the waves. They circle the globe, even sailing beneath the North Pole. This silent patrol can be deadly. Modern submarines are launch platforms for long-range missiles that can be armed with nuclear warheads. But sailing under the water places unique demands on vessels and their crews. Find out about leading submarines from around the world - including their technical specifications. Learn about the history of submarines - from their first use - through incredible developments, right up to the latest, cleverest machines around today. Ultimate Military Machines delves into the incredible world of fighting machines and takes an upclose look at the latest technology used by the army, navy and air forces today. Each title takes an indepth look at one type of military vehicle - from its first use in warfare up to recent conflicts.