The heart of Ironclad Captain are these letters, which Jay Slagle has set in context through the judicious use of published documents, memoirs, and scholarly histories of the navy. The result is a small history of the navy and its officer corps for the middle third of the nineteenth century. Seth Ledyard Phelps was of the Old Navy and the New. As a midshipman and junior officer he served under sail off West Africa, in the War with Mexico, and in the Mediterranean and Caribbean. As a senior officer in the river squadrons of the Civil War he saw combat at its closest. Phelps, a native of Chardon, Ohio, was a prolific and observant correspondent. His private letters, to his wife, his father, and to political patrons and other naval officers, are among the most compelling and descriptive extant.