From his second-floor apartment at the counterculture crossing of Haight and Ashbury streets, Arthur Evans watches a new generation of wayward youth invade his free-spirited neighborhood. The former flower child was among the legions of idealistic wanderers who migrated here during the Vietnam War to "tune in, turn on and drop out." They're known as gutter punks, these homeless kids with dirty dreadlocks and nose rings, lime-green mohawks and orange spray-painted faces, who panhandle with cardboard signs that riff on their lifestyles. "Please Help Us Get Un-Sober," one reads. Another: "Please Give Us Weed, Beer or Money." Sometimes aggressive, they...