Glen Denny's first outdoor experiences came through fly-fishing trips into the Sierra with his father. When Denny moved to Yosemite in 1958 to learn to climb, the first ascent of El Capitan was under way. Inspired by this historic event, he was soon climbing the most challenging routes in Yosemite Valley, including some of the early ascents of El Capitan, with many of the big-wall pioneers of the late '50s and early '60s. Among his partners were legendary climbers Warren Harding, Royal Robbins and Layton Kor. His first ascents include the west face of the Leaning Tower, the Prow on Washington Column and the Dihedral Wall of El Capitan. Originally self-taught, Denny began photographing Yosemite climbs and climbers in the early 1960s before studying photography and filmmaking at San Francisco State University, where he earned a master's degree in fine arts. His climbing films have won awards at several film festivals, and his photography has appeared in a number of publications, culminating in his prize-winning 2007 book, Yosemite in the Sixties. His latest book is Valley Walls: A Memoir of Climbing and Living in Yosemite. Denny lives in San Francisco.