Ever since it was first formulated a century and a half ago, the Second Law of thermodynamics (or "law of entropy increase") has had an air of mystery about it. Why is it true? Is it even always true? In this book, Stephen Wolfram builds on recent breakthroughs in the foundations of physics to finally provide a resolution to the mystery of the Second Law, elegantly showing how it emerges as a general feature of processes that can be described computationally,...