"Look, if I have to explain the meaning of existence," God tells a newly arrived soul, "then it isn't funny." There's nothing childish about cartoons, of course, which often use humor to address the Big Subjects in a form that we can handle. Exploring this underappreciated art form, the authors of Plato and a Platypus Walk into a Bar prove yet again that philosophy can inform our lives. While delving into the thought-provoking possibilities inherent in a series of contemporary one-panel cartoons, Thomas Cathcart and Daniel Klein offer a crash course in what the great philosophers—from the ancient Greeks to the French existentialists—can teach us about religion, gender, knowledge, morality, and the meaning of life.