Two Years Before the Mast by Richard Henry Dana Jr.

Richard Henry Dana Jr. was an American lawyer, politician, and author who is best known for writing the classic memoir Two Years Before the Mast. Dana was also notable for being a supporter of fugitive slaves and freedmen.

Two Years Before the Mast, published in 1840, was written after Dana's two-year sea voyage on board a merchant ship.  Dana went on the trip in hopes that it would help his vision which was affected by a bout with the measles.