Richard Feynman, the Albert Einstein of the second half of the Twentieth Century, once remarked that if someone claimed to understand quantum theory, he was either lying or crazy. "If you understand quantum theory, you don't understand quantum theory." The weird and elusive domain of elementary particles is indeed a domain of an idiotic nature for the human mind. You can claim at most that you understand the mathematical images that represent this microworld.

*Quantum Man: Richard Feynman's Life in Science* is a biography, although an irregular one. Most biographies aim to elucidate the person behind the main character of the book and their interactions during their life. Lawrence Krauss takes a slightly different route. He tries to determine what Richard Feynman achieved as a scientist, without too much detail about his personal life. He doesn't seem to be too interested in what motivated Feynman in life, but he's quite interested in what Feynman found fascinating in science. That science has to be translated mainly to quantum theory and especially quantum electrodynamics (QED), the world of electrons in their quantum field.

Krauss explains how Feynman develops a new understanding of QED, first thinking he was just making up a construct to evade problems, later realizing he indeed had discovered something fundamental about quantum mechanics. But before everything else, Krauss explains why Feynman the scientist chose his battles with math and nature. A deep and sometimes unsettling wish to find out everything by himself. Unsettling on one side because he refused to look at other's achievements when stuck in a rut, on another side because he had the ability to find out anyway, and often better than others. It seems a tragic trade-off; maybe if Feynman had invested more in collaboration, he would have achieved less impressive results.

It's always interesting to know where a specific drive comes from. What made Feynman so obsessive about the scientific choices he made? How was his personal life related to his science? Of course Krauss touches on Feynman "the man", but sparsely.

In the end *Quantum Man* is a book about the development of quantum theory, illustrated an illuminated by Feynman and his work as a scientist. It sometimes means it's more of a quantum theory book than a biography, and Feynman - who certainly was a character - never comes close. It doesn't make the book bad, but from the perspective of human interest a bit meager. On the side of quantum theory and Feynman's achievements however, the book delivers all you want to see delivered. But it could have been so much more.

I started with the observation that Feynman can be called the Einstein of the second half of the Twentieth Century. In a way he was even more brilliant than Einstein. While Albert Einstein developed a genial way of thinking about the universe, he became quite a conservative character when it came to later developments; especially quantum theory. Everyone knows the "God doesn't throw dices" and "spuckhafte Fernwirkung" (spooky action at a distance) remarks, showing that he rather was safe than sorry when it came to the quantum domain. Feynman however never relented: if the idea seemed idiotic to everyone, Feynman wouldn't walk away from the intellectual challenge to make sense of the seeming nonsense.

Richard Feynman gets his admiration from Lawrence Krauss when it comes to that, but looking behind the chalkboard and papers full of crazy and great ideas would have made Feynman so much less elusive than the quantum world he knew so well.