"On his regular walk one morning, Spike Carlsen realized there was an entire world outside his front door that he knew nothing about. How does that fire hydrant work, he wondered? Why are street lights shining more brightly than ever before? And, on a more personal level, why does an easy stroll around the neighborhood always leave him feeling more creative and spry, better able to take on the day? A simple walk around the block set Carlsen off on...