John and Paul were more than friends, collaborators or rivals in the sense we normally understand those terms. They were both exceptionally intense young men who had the fabric of their world ruptured at a young age. They longed to connect - with each other, with audiences. The pop song was a container into which they poured everything they couldn't say; their pain or joy, or both at the same time. The Lennon and McCartney partnership was responsible for 159 of The Beatles' 184 recorded original songs. Even when their relationship deteriorated, their creative partnership flourished - during the last year of The Beatles they were still prolific collaborators. After the break-up, they maintained a dialogue at a distance, in songs full of recrimination, regret, and affection. This book focuses on what lay at the heart of this phenomenon: the alchemy of two young men.