When asked to define what makes a sport extreme, one practitioner--a rock climber in the countryside and a skateboarder in the city--replied, "It's a sport where you may well hurt yourself, or worse." Readers of this compelling book will learn all about these alternative, edgy sports and what it takes to parachute from an airplane, zip-line through the air, or brave the possibility of a flash flood by venturing into a canyon. Or, readers may simply be satisfied to read about the popular X Games, during which they can sit back and watch the pros take the risks.