Freeman Dyson in the New York Review of Books:
Jim Holt’s Why Does the World Exist?: An Existential Detective Story is a portrait gallery of leading modern philosophers. He visited each of them in turn, warning them in advance that he was coming to discuss with them a single question: “Why is there something rather than nothing?” He reports their reactions to this question, and embellishes their words with descriptions of their habits and personalities. Their answers give us vivid glimpses of the speakers but do not solve the riddle of existence.
The philosophers are more interesting than the philosophy. Most of them are eccentric characters who have risen to the top of their profession. They think their deep thoughts in places of unusual beauty such as Paris and Oxford. They are heirs to an ancient tradition of academic hierarchy, in which disciples sat at the feet of sages, and sages enlightened disciples with Delphic utterances. The universities of Paris and Oxford have maintained this tradition for eight hundred years. The great world religions have maintained it even longer. Universities and religions are the most durable of human institutions.
According to Holt, the two most influential philosophers of the twentieth century were Martin Heidegger and Ludwig Wittgenstein, Heidegger supreme in continental Europe, Wittgenstein in the English-speaking world.