The Mexican War (1846-48) as a cultural phenomenon--smoothly handled despite occasional lapses and fits of academic high seriousness. Drawing largely on popular books and periodicals rather than on the more-familiar official sources, U. of Illinois historian Johannsen (prize-winning biographer of Stephen A. Douglas) neatly tags the different components of the country's almost hysterical enthusiasm for the war--among them millenial republicanism, unabashed Anglo-Saxon racism, plain old national chauvinism, and heavy doses of romantic claptrap about the revival of medieval chivalry. Better still are his descriptions of the conflict's impact on American patriotic symbols and music (Old Glory, the bald eagle, Yankee Doodle), on West Point (this was the Academy's first war), on public interest in the careers of Washington and Napoleon, on the creation of new national heroes (some familiar, like Zachary Taylor, others more obscure, like Alexander W. Doniphan), on public taste (it launched a fad for moustaches and ""cigarritos""), and even on public speech (witness the popularity of the expression, ""to see the elephant"")--not to mention the war's implications for travel literature, sightseeing, popular verse and fiction, theater, and music. The bad news is that Johannsen does not give a satisfactory account of opposition to the war--his impatience with the abolitionists is particularly unfortunate--and his occasional attempts at analytical rigor are far from impressive (""one indicator of its importance was the depth to which it penetrated the national psyche""). These defects are far from fatal, however, and what remains is richly informative.