Long before “sustainable” became a buzzword, intellectuals wondered how long industrial society could survive. In “The Idea of Decline in Western History,” after surveying predictions from the mid-19th century until today, the historian Arthur Herman identifies two consistently dominant schools of thought.

The first school despairs because it foresees inevitable ruin. The second school is hopeful — but only because these intellectuals foresee ruin, too, and can hardly wait for the decadent modern world to be replaced by one more to their liking. Every now and then, someone comes along to note that society has failed to collapse and might go on prospering, but the notion is promptly dismissed in academia as happy talk from a simpleton. Predicting that the world will not end is also pretty good insurance against a prolonged stay on the best-seller list. Have you read Julian Simon’s “The State of Humanity”? Indur Goklany’s “The Improving State of the World”? Gregg Easterbrook’s “Sonic Boom”?

Good books all, and so is the newest addition to this slender canon, “The Rational Optimist,” by Matt Ridley. It does much more than debunk the doomsaying. Dr. Ridley provides a grand unified theory of history from the Stone Age to the better age awaiting us in 2100.

It’s an audacious task, but he has the intellectual breadth for it. A trained zoologist and former editor at The Economist, Dr. Ridley has established himself in previous books, like “The Origins of Virtue” and “Genome,” as the supreme synthesist of lessons from anthropology, psychology, molecular genetics, economics and game theory. This time he takes on all of human history, starting with our mysteriously successful debut. What made Homo sapiens so special? Dr. Ridley argues that it wasn’t our big brain, because Neanderthals had a big brain, too. Nor was it our willingness to help one another, because apes and other social animals also had an instinct for reciprocity.