Halfway into Matt Richtel’s engaging and lively romp through the wide world of creativity, he collides headfirst with the conundrum every writer tackling subjects like creativity or humor eventually confronts: how to shed light on the topic without spoiling the fun. When he asks the wildly talented musician Rhiannon Giddens to describe her creative process, she says, “Sometimes I get an idea and it just goes and it goes … It’s magic.”