The first in a trilogy, Grass Beyond the Mountains is a story of discovery and endurance on North America's western frontier by three good old-fashioned cowboys.     With laconic cowboy humor and the ease of a born writer, Richmond Hobson describes the life-and-death escapades, the funny and tragic incidents peopled with extraordinary frontier characters, in a true adventure that surpasses the most thrilling Wild West fiction.      In the fall of 1934, three cowhands with a dream of owning a cattle ranch made their way from peaceful Wyoming to the harsh, uncharted territory of the British Columbian interior. In conditions as challenging as any encountered by the western frontier pioneers of a hundred years earlier, the three men and their equipment-laden horses conquered the tortuous miles over narrow passes and mountain summits, hewed their first cabin from virgin timber, and attempted to carve out a space for themselves on the unforgiving landscape.      Gritty, fun, and endlessly entertaining, Hobson's story is sure to entertain country- and city-dwellers alike.