The Rational Optimist is a 2010 popular science book by Matt Ridley, author of The Red Queen: Sex and the Evolution of Human Nature. The book primarily focuses on the benefits of the innate human tendency to trade goods and services. Ridley argues that this trait, together with the specialization linked to it, is the source of modern human civilization, and that, as people increasingly specialize in their skill sets, we will have increased trade and more prosperity.