I defy you to find a writer, a good writer, living or dead, who has talked about money as incessantly and with as much impenitent relish as John Gregory Dunne. He lived, it seems, for the grubby little details: flip through his interviews and you’ll discover a recitation of dollar figures, buyout clauses, basis points. The man rattles off contract terms as a priest recalls the catechism. Here are some snippets from a 1996 interview ostensibly on the “art of screenwriting”: He paid off our contract at forty cents on the dollar…. To our amazement it sold to some studio, I think it was CBS , which paid us fifty thousand dollars…. We’ve written twenty-three books between us and movies financed nineteen out of the twenty-three…. Six figures a week if you’re any good, hundred grand at the minimum…. Look. It pays a lot and it’s fun. It does sound like fun.…