Space is dominated by plasma and a myriad of physical processes through which it has been evolving for billions of years. In our effort to understand what the universe has been and what it will become, we turn to the nature of matter, space, and the various interactions that change this environment. Our contact with the remote regions of the universe is dominated by the photons and high-energy particles produced there long ago, with light often the result of physical processes that involve particles accelerated to high energy. Developing our knowledge of particle acceleration across all spatial scales and energies is one of the keys to understanding the evolving universe. It is also the subject of this book.