Joshua Wolf Shenk offers an intriguing look at the nature of creative partnerships in Powers of Two: Finding the Essence of Innovation in Creative Pairs. His subjects range from the musical (Lennon and McCartney) to the scientific (Watson and Crick), from the literary (Melville and Hawthorne) to the technical (Jobs and Wozniak). From these dozens of case studies, Shenk synthesizes the patterns. What happens when creative pairs meet? (Hint: It’s often like falling in love.) When does the really good work get going? Why do such partnerships often end?