Muir was an early explorer of California (on foot, incidentally) and was the force behind the creation of Yosemite National Park. He’s also the guy on the California quarter. (As an aside, see our own cranky take on quarters and heroes.)
In a brisk 7900 words, Muir tells of a perilous day on an Alaskan glacier with only a plucky mutt, Stickeen, for a companion. It’s a true story, too.