The author of more than twenty books on scientific and historical subjects, David Owen presents an authoritative yet highly readable account of the ongoing battle between naval forces above and below the sea's surface. Without question, the submarine was the most potent purely naval weapon of the twentieth century, yet the fact that it was usually defeated is an important part of the story described in this book. With the support of nearly 200 illustrations, the author examines both the successful innovations and the inevitable counter-measures made by each side in their lethal struggle for supremacy. Known for picking just the right incident to illustrate a point, Owen fills his book with examples of individual heroism and devotion to duty along with accounts of the ingenuity, originality of tactical thought, and technological advances to provide a complete picture. He shows clearly that development was not a straight line--wrong ideas and assumptions sometimes led to defeat and disaster. Concluding the book is a survey of recent ASW developments carried out by teams of scientists, engineers, commanders and crews of ASW aircraft, ships, and other submarines working together to defeat the current threat of hostile raiders who hide in the ocean depths.