Ultra-marathoner Dean Karnazes claims "There is magic in misery." While it would be easy to write off his habit of running for 100 miles at a time - or longer - as mere masochism, it's impossible to not admire his tenacity in pushing his body to reach one extreme goal after another. Sure, it's gory to read about how he lost one of his big toenails from shoe friction during the Western States Endurance Run. But what registers more is that here's a guy competing in an event that includes 38,000 feet of elevation change--the equivalent of scaling the Empire State Building 30 times.

Despite his considerable athleticism, "Karno" argues that the first half of any race is run with one's body, and the second half with the mind. Without delving into excessively touchy-feely territory, he explores "the possibilities of self" as he completes an ultra-marathon in 120-degree heat in Death Valley, and later the first-ever marathon at the South Pole. It's an odd combination: a California surfer dude contemplating how, as Socrates said,