BOOK REVIEW • Lethal Tides: Mary Sears and the Marine Scientists Who Helped Win World War II

Although Thomas Jefferson had recognized the need for mapping and charting the waters of the young United States in 1807, it wasn’t until 1830 that the US Navy established the Depot of Charts and Instruments, which later became the US Naval Hydrographic Office. At the beginning, the Depot was a clearinghouse for navigational equipment and the few foreign charts that were available. The Depot didn’t make its own charts until 1837, with the first one covering Georges Shoal and Bank, from ship tracks provided by Lt. Charles Wilkes. Wilkes later led the famous 1838 US Exploring Expedition that provided the United States its first worldwide mapping coverage (Heynen, 1978).