Among the more than 260 American submarines that patrolled the Pacific during World War II, the USS Swordfish in 1941 was the first to sink a Japanese armed merchant ship, marking the beginning of the submarine's colorful history. A series of seven commanders led Swordfish's 13 war patrols. Each skipper had a distinct leadership style. Some were successful in sinking enemy ships; others returned to port empty-handed. Yet all patrols risked dangerously close encounters with the enemy and the unforgiving nature of the open sea. Drawing on archival sources and interviews with veteran sailors, this first full-length history of the Swordfish provides detailed accounts of each patrol and covers the mysterious disappearance of the legendary submarine on its final mission.