Andrew McAfee wants to cheer you up. If you read his latest book with an open mind, he might well succeed. McAfee, an MIT economist, is joining the New Optimists (Bill Gates, Stephen Pinker, Hans Rosling and others) in trying to persuade us that the world is not going to the dogs. The central claim of “More From Less” is that capitalism and technological progress are allowing us “to tread more lightly on the earth instead of stripping it bare.” Unfortunately, he admits, this good news is hard for many people to believe because catastrophism has such a strong hold on our imaginations.