For author Geoff Nicholson, walking is a source of "self-medication," a tonic that beats back depression and helps him write. The happy result is "The Lost Art of Walking," a rambling man's survey of the oddities and intrigues of putting one foot before the other. Humans have hoofed it for so long that the motion is etched into our very nature: unborn babies, he reports, make walking movements in the womb. Over time, the upright life has inspired a lofty "science, philosophy and literature" of its own, writes Nicholson, who guides readers through pedestrianism's highs and lows while ambling around London, Los Angeles and New York. Walking for pleasure is compared to sex (sometimes banal, sometimes beautiful) and traced to the automobile revolution, which turned walking into a special treat and strollers into rebels without a car. The message: walking is a form of physical and mental exploration. But perhaps Nicholson sells it a bit too well. Reading the book makes you want to put it down and get on your feet.