This is the first book to explore information management at sea as practiced by the U.S. Navy from the Civil War to World War II. The brain of a modern warship is its combat information center (CIC). Data about friendly and enemy forces pour into this nerve center, contributing to command decisions about firing, maneuvering, and coordinating. Timothy S. Wolters has written the first book to investigate the history of the CIC and the many other command and control systems adopted by the U.S. Navy from the Civil War to World War II. What institutional ethos spurred such innovation? Information at Sea tells the fascinating stories of the naval and civilian personnel who developed an array of technologies for managing information at sea, from signal flares and radio to encryption machines and radar. Wolters uses previously untapped archival sources to explore how one of America's most technologically oriented institutions addressed information management before the advent of the digital computer. He argues that the human-machine systems used to coordinate forces were as critical to naval successes in World War II as the ships and commanders more familiar to historians.