The book I read wasTouching the Void written by Joe Simson. Simpson and his friend Simon Yates decided to hike a 21,000 foot peak on the west side of the Siula Grande at the Puruvian Andes which know one has sucsessfully done, when disaster struck and Simpson fell off a vertical ice face and broke his leg. While Yates was lowering him down in the dark simpson slid off another ice face and was dangling 80 feet over a crevasse pulling Yates down with him so yates was forced to cut the rope. Simpson fell and amazingly survived just a couple feet away from the deepest part of the cevasse, because he couldnt climb up it he decided to climbed down to the bottom and found a hole out the side of the mountain where he found the trail home. Simpson had to crawl 4 miles with no food or water for almost 5 days until he finally made it back to base camp almost dead where Yates was just about to leave for home.