Glass (Bad Guys) serves up another slice of rough-and-ready Americana with this rootin'-tootin' tribute to the fur trappers and frontiersmen of the Old West. "Mother Nature, they said, stretched the truth taller and wider in the Rocky Mountains, just naturally making grand liars out of ordinary frontier yarn spinners," he writes. He proves the point with profiles of seven mountain men, spotlighting exploits both real and imaginary. There are grizzly encounters, cabin fever–inspired brawls and brushes with death, as well as outrageous yarns about horses that jump across canyons in their sleep. One particularly blithe raconteur claimed to have been dangled over a precipice by a giant Blackfoot: "At this point in his story, Jim would hesitate... until some greenhorn demanded impatiently, 'Well, what happened?' Then Jim Bridger... would reply simply, 'I got kilt!' " Explanations of the Louisiana Purchase, the Lewis and Clark expedition and the fur trade orient readers at the beginning of the book; at the end, readers will enjoy the pictorial list of "mountain man necessaries" and the glossary, which identifies such terms as "porkeater" (greenhorn) and "didins" (food). Glass's language fairly bristles with color, and his busy, rough-hewn style complements the hyperbolic humor of the vignettes without sacrificing a hold on realism. Ages 8-12. (June)