One of the most influential writers on seapower, Alfred T Mahan, wrote voluminously (here is a bibliography of his work; access to many of his writings online are available as well), expressing his opinions and research over a vast panoply of naval topics. However, finding more intimate knowledge of the man himself is a bit more elusive. That can be solved by having recourse to his From sail to steam; recollections of naval life that was published in 1907. It is an anecdotal telling of his life from his first sea service until his presidency of the Naval War College.
Autobiography of Alfred T Mahan