Open Book is a historic rock climb located on Tahquitz Rock in Southern California. When Royal Robbins did the first free ascent in 1952 it was one of the hardest routes in the country and became the first climb given the grade of 5.9 on the Yosemite Decimal System. To this day Open Book remains an all-time classic and an aspiring tick for any leader.
The route was first climbed using aid in 1947 by John Mendenhall and Harry Sutherland, two leaders of the Sierra Club. Mendenhall famously fashioned wooden pitons out of 2×4 lumber which he pounded into the wide crack on the second pitch. He then attached stirrups to the pegs and stood up in them to make upwards progress.