ONE night last year I called my friend Oliver and told him to meet me on the roof of our apartment building. He lives three flights down from me. I had pulled together a simple dinner — roast chicken, good bread, olives, cherries, wine. We ate at a picnic table. I’d forgotten wineglasses, so we traded swigs out of the bottle. It was summer. The sun was setting on the Hudson. Neighbors were enjoying themselves at nearby tables. The breeze was nice. The surrounding cityscape looked like a stage set for a musical.