Published in 1924, this non-fiction adventure recounts Zane Grey's real-life experiences capturing mountain lions in the rugged Grand Canyon. Accompanied by famed plainsman Buffalo Jones and a Navajo guide, Grey sets out on a thrilling expedition to lasso lions for preservation rather than sport. The narrative blends humor, danger, and the grandeur of the canyon, providing a vivid depiction of early conservation efforts. Grey's detailed descriptions of the landscape and wildlife, combined with the physical challenges of roping lions, offer an exhilarating and unique perspective on life in the American West.