Elements of Military Art and Science: Or, Course of Instruction in Strategy, Fortification, Tactics of Battles, &C.; Embracing the Duties of Staff, Infantry, Cavalry, Artillery, and Engineers; Adapted to the Use of Volunteers and Militia; Third Edition; with Critical Notes on the Mexican and Crimean Wars.

This is American military education on the eve of catastrophe. Originally delivered as lectures at Boston's Lowell Institute, Halleck's textbook was designed for volunteer and militia officers - citizen-soldiers who might suddenly find themselves commanding troops without formal training. It synthesizes European military theory (especially the influential Jomini) with practical American experience, covering strategy, fortification, battlefield tactics, and the specific duties of infantry, cavalry, artillery, and engineers. What gives the book its edge is its moment: written as the Mexican War unfolded, with later editions incorporating hard-won lessons from that conflict and the Crimean War. Halleck would go on to become Lincoln's general-in-chief, and reading this now feels like peering into the mind of antebellum American military leadership - men whose assumptions about warfare would be bloodily tested when the Civil War began. It is, in essence, the last confident statement of 19th-century military orthodoxy before that orthodoxy shattered.