The “Second Happy Time” was the informal name given to the phase of the battle of the Atlantic when German U-boats attacked both merchant and U.S. naval vessels along America’s east coast. With tankers burning and petrol rationing in New York City, the U.S. Navy seemed powerless to stop the deprivations of Hitler’s marauding U-boats. Ken Brown seeks to explain how the United States responded to these deadly assaults and looks at the steps that the Navy Department took to train the men, harness the scientists, and make the organizational changes that were required to defeat the German threat.