The Regular Army Before the Civil War, 1845-1860
"The fifteen years that preceded the outbreak of the American Civil War were eventful ones for the U.S. Army. After invading and defeating Mexico, the Army dispersed across the vast Western frontier, subdued American Indian tribes, explored and governed new territories, and generally worked to maintain peace. At the same time, it supported national development through mapping and engineering projects, grew in size, and undertook important steps toward modernization" --publisher.