The universe is made of bits. The way in which the universe registers and processes information determines what it is and how it behaves. It has been known for more than a century that every piece of the universe - every electron, atom, and molecule - registers bits of information. It is only in the last ten years, however, with the discovery and development of quantum computers, that scientists have gained a fundamental understanding of just how that information is registered and processed. Seth Lloyd calls this fundamental understanding of the universe in terms of information processing 'the computational universe', and the purpose of this book is to show how the programmed, computational universe works. Starting from basic concepts of physics, Programming the Universe shows how all physical systems register information. It gives an accessible account of how information is stored and processed at the level of electrons, atoms, and molecules. It shows how the information processing power of the universe can be harnessed to build quantum computers and explains how the universe itself behaves like a gigantic computer, transforming and processing information. It traces the history of information processing from the big bang to the present day, and reveals how the computational ability of the universe promotes the evolution of complex structures such as life. Programming the Universe is the story of the universe and the bits it is made of.