Relativity plays an important role in atomic nuclei, and, since the early 1970s, there has been increasing interest in, and literature on, the nucleus as a relativistic system. In fact, the relativistic treatment provides a powerful method to describe nuclear structure and reactions. It is thus an ideal time to collect and review the important landmarks in this book. Directed to advanced students and researchers, it explains both the underlying relativistic theory and compares predictions with actual experiments.