Alfred Thayer Mahan (1840-1914) ws a US naval officer and historian who has been described as "the most important American strategist of the 19th century." His book The Influence of Sea Power Upon History, 1660-1783 (1890) won him immediate recognition, particularly in Europe, and with its successor, The Influence of Sea Power Upon the French Revolution and Empire 1793-1812 (1892), made him world-famous. After studying at Columbia, Mahan entered the Naval Academy where he graduated second in his class in 1859. Commissioned as a lieutenant in 1861, he served the Union in the Civil War as an officer on USS Worcester, Congress, Pocahontas, and James Adger, and as an instructor at the Naval Academy. In 1865 he was promoted to lieutenant commander and then to commander (1872), and captain (1885). In 1885 he was appointed as lecturer in naval history at the Naval War College and was directed towards writing on the influence of sea power. He took over as President of the College from 1886-89 and again from 1892-93. Between 1889-92 he was engaged in special service for the Bureau of Navigation, then in 1893 was given command of the new protected cruiser Chicago on a visit to England. He returned to lecture at the War College and in 1896 retired from active service, returning briefly to duty to consult on naval strategy during the Spanish-American War. Mahan continued to write, publishing numerous books on naval subjects, including Types of Naval Officers (1901) which gives an account of naval warfare at the beginning of the 18th century, and of its subsequent development during the sail period.