‘H ow far do you want to go back?” In his office overlooking Soho Square in London, Paul McCartney and I sit together on a small sofa, reminiscing. The room smells deep and resinous and faintly ecclesiastical. There is a large green glass candle on the windowsill, and beyond, a view of plane trees, a flood of early afternoon sunlight. The building was bought by McCartney in 1974, and has long served as a home for his publishing company and other enterprises. On another floor, two members of his team survey prints of his late wife Linda’s photographs, spread out on the boardroom table. An assistant is busy arranging a bagel order, while in the small lift, someone is ferrying a trolley full of drinking glasses up to the kitchen, a convivial clink-clatter echoing through the floors. McCartney and I are discussing the earliest sounds he can remember, what Seamus Heaney once called “linguistic hardcore”; that is, the sounds that unconsciously bed the ear, providing a kind of aural foundation.…