I recently listened to the sociologists-epidemiologists Richard Wilkinson and Kate Pickett discussing their book The Spirit Level on NPR. A few days later, they were on Book TV and soon I was reading a lengthy piece on them in the London Review of Books. The publicity worked and I bought the book. By the way, a spirit level is the same as a bubble level, the carpenter’s device containing a bubble in liquid to ensure whatever’s being constructed is plumb.