Merrill (not to be confused with James Merrill the poet-novelist) writes staccato action scenes by the bushel in this history of the United States Cavalry and its horse units. The horse cavalry officially had its inception in 1833 as the frontier moved westward and away from the heavily forested East. The first dragoons were awesomely uniformed and ornamented and when they rode into a Commanche village, the Indians gaped as if the horsemen ""had come from the moon."" A major part of the text is given over to the Civil War career of George Armstrong Custer and his later paranoid wig out at Little Bighorn. This is the umpteenth recent study of Custer, the best of which are Mari Sandoz' The Battle of The Little Bighorn (p. 342) and Terrell & Walton's Faint the Trumpet Sounds (p. 566). More interesting by now than Custer is Merrill's description of ""Black Jack"" Pershing's United States Punitive Expedition into Mexico to get Pancho Villa. Villa had raided Columbus, New Mexico. Fighting Indians, Mexicans and the Confederate Army, the U.S. Cavalry became the Army's glamour troops. Their most famous charge was in the Spanish American War with Teddy Roosevelt's Rough Riders. Mounted soldiers proved useless in WWI and the cavalry was finally mechanized just after Pearl Harbor. Very readable.