During my entire research life, friends and curious people have asked me to explain what was going on in quantum gravity research. How was it possible to study new ways of thinking about space and time? Over and over again I have been asked to write a popular account of this research. While books on cosmology or string theory abound, a book describing the research on the quantum nature of space and time, and on loop quantum gravity in particular, did not yet exist. I have long hesitated, because I wanted to concentrate on research. Some years ago, after completing my technical book on the subject, I felt that the collective work of many scientists had moved the topic to a stage mature enough for a popular book. Ge landscape we are exploring is enchanting: why keep it hidden?
As a whole, this is a travel book describing one of the most spectacular journeys that humanity has taken: a journey out of our limited and parochial views of reality, towards an increasingly vast understanding of the structure of things. A magical journey out of our common-sense view of things, far from complete.
Our book explores one of the most profound frontiers of modern physics: the unification of quantum mechanics and general relativity. Written with clarity and depth, the book examines how space, time, and matter may emerge from quantum principles, shedding light on theories such as loop quantum gravity and beyond. Balancing rigorous science with accessible explanations, it guides readers through the conceptual and mathematical challenges of reconciling the large-scale structure of the universe with its smallest quantum constituents. Both a roadmap of past achievements and a vision of future discoveries, this book offers a compelling journey into the quest for a quantum theory of spacetime.