In his second book in this biographical series on philosophy, Gottlieb focuses on the thinkers of the Enlightenment from Descartes to Voltaire. There's a special focus on undercutting misguided conventional wisdom. For example, while Descartes took cogito, ergo sum as his first axiom, he believed that soul and body were deeply connected, even if he couldn't quite articulate how, as opposed to the strict divide that has garnered the name "Cartesian dualism". Hobbes, while valuing political stability, was hardly a totalitarian. Locke's treatises were more conservative than liberal, Rosseau rather a misanthrope and critic of the whole project, etc.

As before, Gottlieb blends a solid summary of these thinkers lives with these thoughts, though he doesn't quite manage to synthesize what the Enlightenment was, or why the cumulative efforts of all these thinkers deserve to be called the Enlightenment. Still, an interesting and informative book.