This book introduces readers to the underwater world of submarines, showing them how these amazing watercraft have used stealthy secret attacks throughout history to revolutionize ocean warfare. Vibrant images and detailed diagrams of submarines from the U.S., Britain, Russia, and Germany are featured, from U-boats of the early 20th century to today’s fastest and most powerful nuclear submarines. Readers will see firsthand how developments in technology have allowed submarines to patrol at greater and greater depths undetected.