The U.S.-Mexican War of 1846-1848 remains controversial even today. The California campaigns of this conflict introduce the reader to the Californios (the colorful inhabitants of Alta, or Upper, California); to the American and other adventurers who arrived after them; and to the local Indians, who were always there.

The real prize of the war was California. For the Mexican government to go to war against its more powerful northern neighbor was an act of folly. The Californios themselves had only ambiguous loyalties to the central government and only the most minimal military capabilities.

The net result of the war was that Mexico was forced to surrender to the United States more than half a million square miles of its territory. This surrender contributed to a legacy of Mexican humiliation, distrust, and bitterness towards the United States that has never dissipated entirely.