Jason Griffin straps his right arm in bandages, preparing himself to grip the reins a wildly bucking bronco. Tall, broad-shouldered, with a rough beard, he steps into his cowboy boots, fits a Stetson hat and heads out to meet his mount in the rodeo arena. Griffin is a four-time world champion bareback bucking horse rider—competing in a sport that began in the 19th century heyday of the Wild West. With each victory—he has also won three all-round rodeo championships—the Texan raises awareness of a strong tradition which is rarely seen in the many novels, films and television series dedicated to the tales of the old West: The historic story of America's Black cowboys. On cinema screens and paperback covers, the cowboys of old were heroic, hard-bitten and—almost always—White. In reality, the American West of the 1800s was traversed by an assortment of Black, White, Mexican…