Michio Kaku - The God Equation - The Quest For A Theory Of Everything (Allen Lane, 2021) ****

Michio Kaku is professor of physics at the City University of New York, and one of the co-founders of the string field theory in theoretical physics. In "The God Equation", he describes the wet dream or the holy grail of all theoretical physicists: to find a unifying theory that combines quantum physics with Einstein's relativity theory and other astronomical theories, so that all the forces of the universe can be explained by one comprehensive set of rules. 

Kaku is a wonderful writer, who takes even non-physicists like myself by the hand to introduce them to the weird world of modern day physics. The strength of his narrative is that he also talks about the people, about how for instance Heisenberg and Pauli differed in their opinion from Niels Bohr. "After his talk (at Columbia University in 1958), Bohr stood up and said: 'We in the back are convinced your theory is crazy. What divides us is whether your theory is crazy enough'". It is fascinating reading, and one of the many popular science books I have read on physics, but it remains totally incomprehensible. It is hard to imagine what some of the theories may actually mean. What is a universe with 11 dimensions? What does it mean that there are multiple universes? And will we ever reach them through wormholes? 

In the end, the questions remain. But the journey to find the answers is by itself fascinating.