Wheeler is gracious to a fault; one colleague describes him as "a gentleman hidden inside a gentleman." But that courtly demeanor also hides something else: one of the most adventurous minds in physics. Instead of shying away from questions about the meaning of it all, Wheeler relishes the profound and the paradoxical. He was an early advocate of the anthropic principle, the idea that the universe and the laws of physics are fine-tuned to permit the existence of life. For the past two decades, though, he has pursued a far more provocative idea for an idea, something he calls genesis by observership. Our observations, he suggests, might actually contribute to the creation of physical reality. To Wheeler we are not simply bystanders on a cosmic stage; we are shapers and creators living in a participatory universe.