There are the rich and there are the very rich, and while the very rich exhibit varied demographic characteristics, the family at the center of Jenny Jackson’s sparkling debut novel, “Pineapple Street,” is of a highly specific sort: the pedigreed, never-touch-the-trust-fund-principal, tennis-playing, old-money-Brooklyn WASP.

I had always dreamed of a job that engaged in some aspect of the business of books. Although I was writing novels and taking on freelance work—for a time I became the queen of the 800-word feature story for a couple of international newspapers, accepting any assignment that came along, from writing about children’s birthday parties to the black market economy in India—I had not had a steady paycheck since my twenties.

“It seemed to be one of life’s wonders,” observes Sherwyn Sexton, the not wholly unlikable cad at the center of Fay Weldon’s lively if sometimes frustrating new novel, “Before the War,” “that nothing happens and nothing happens and all of a sudden everything happens.”