The Rational Optimist is a bit like Candide, the character in Voltaire's book. He kinda believes this is the best of all possible worlds and that the future will be even better. But unlike Candide, he bases his optimism on economics. Humans will adapt, specialize, trade while poverty and violence will decrease. This is thanks to the catallaxy, i.e. Hayek's name for the spontaneous order created by exchange and specialization.
This is the book you'd expect from an author who has a PhD in zoology and worked 10 years for The Economist. It's full of interesting material, melting Adam Smith ideas with Darwin's. My favourite chapter is about how markets make people nicer, increases mutual trust and reciprocity. He's quite convincing, going through anthropological, empirical and even experimental evidence.
But I have to admit I skipped a few pages here and there. While anecdotes and evidence are always interesting, we get the point quite fast... It's the gains from trade.