Guns Along the Rio Grande: Palo Alto and Resaca de la Palma is an engaging account of the period of distrust and misunderstanding that preceded the opening of hostilities between the United States and Mexico. In his highly readable essay, Stephen A. Carney traces the tensions that proved to be the catalyst for the opening battles at Palo Alto and Resaca de la Palma on 8 and 9 May 1846, covering the strategic setting and each operation in detail. Army of Occupation commander Brig. Gen. Zachary Taylor ultimately won decisive tactical victories against a numerically superior enemy, highlighting the value of United States Military Academy graduates commanding the regulars and validating the existence of both the professional army and the academy at West Point. In a wider historical perspective, these battles represent early instances in which the U.S. Army enjoyed technological superiority over a conventional foe, the battle at Palo Alto proving that American artillery was one of the most advanced in the world and that it could dominate an open battlefield. The result, according to Carney, was victory with marked savings in American lives. This circumstance, little noted at the time, was in fact the first harbinger of what would become a dominant theme in American military experience during the second half of the twentieth century. Junior officers learned the trade of war in the battles at Palo Alto and Resaca de la Palma, and soldiers today will readily identify with their experiences in projecting force and conducting operations in hostile territory.