Novel, Donald Knuth.
I've loved this novel ever since I was a math-loving kid of 14 or so. Here we have a nice American couple of kids out on an island in the Indian Ocean....perhaps the LOST island? Anyway, they're bored, find a mysterious tablet, and spend the rest of the book talking about math, philosophy, sex, theology, coconuts, math, fish and sex. Alice is the analytic one, Bill more intuitive, and it's true, the erotic content is a trifle dated these days...but in a good way, I think, it helps to leaven the discussions, the same way that the Marquis de Sade's (sorry, Dr. Knuth, it's the only comparison that springs to mind) dialogues are unreadable without the "other" material (whether you're referring to the politics or the sex, is your choice.) Anyway, hats off to a fun book!