You can read this book in a couple of hours, easy, but I took my time with it and reread a few of the latter chapters because the concepts of Einstein and quantum mechanics are really difficult for me to grasp, even with Rovelli’s excellent writing and explanations. This book is meant for the general public and is a summation of what we know, what we know we don’t know, and what questions we’re still asking about how the universe is made and works. I by know means now feel like an expert on the subject, but I can listen to experts (or tackle more in depth books) discuss physics concepts and follow along. A great book for the scientifically curious and an enjoyable read of wonder at the natural world.