The “Mexican Frontier, 1821-1846: The American Southwest under Mexico” is a textbook from the “Histories of the American Frontier Ser.” published by the University of New Mexico Press in 1982. Written by David J. Weber, the book explores the history of the American Southwest during the 19th century, specifically focusing on the Mexican frontier period. With 440 pages, the trade paperback offers a comprehensive look at this subject area in English language. It provides valuable insights into the complexities of the region and its significant historical events.