If you liked Rovelli’s last book, Seven Brief Lessons on Physics, you will be excited and challenged with his new one, Reality Is Not What It Seems: The Journey to Quantum Gravity. Be prepared to really dive into the fundamentals of quantum gravity, one of the most beautiful and thought – provoking theories in the world of physics.

Rovelli takes us on a fascinating journey spanning 2,500 years of evolution in physics, starting with the ideas of ancient Greeks and especially Democritus of Abdera to the Newtonian revolution and the genius of Albert Einstein to the strange world of loop quantum gravity. A world where time does not exist and physical reality is not what it seems.

Quantum gravity combines general relativity (GR) and quantum mechanisms (QM) to find a new synthesis that will help us understand a world in which quanta and curved space exist. It is a major challenge and most of the physicists, with the exception of Dirac, Feynman, Weinberg, Penrose, Hawking, among others, in the second half of the 20th century have ignored this challenge.

In science, writes Rovelli, “there are no secure recipes for discovery and it is important to explore different directions at the same time.” Currently, string theory and loop quantum gravity are the two most developed paths.   Carlo Rovelli belongs to the school of loop quantum gravity where the central idea is that space is not a continuum, “it is not divisible ad infinitum” but it is quantified, “formed of ‘atoms of space,’ a billion billion times smaller than the smallest of atomic nuclei.”

Rovelli, with great elegance and clarity, presents leading-edge research in the revolutionary field of loop gravity theory. It is an intellectually challenging book, accessible to all readers but not for the faint-hearted.