David J. Griffiths received his BA (1964) and PhD (1970) from Harvard University, and was Professor of Physics at Reed College from 1978 until 2009. He is author of Introduction to Electrodynamics (4th ed. Cambridge University Press, 2017), Introduction to Quantum Mechanics (3rd ed. with Darrell Schroeter, Cambridge University Press, 2018), Introduction to Elementary Particles (2nd ed. Wiley, 2008), and Revolutions in Twentieth-Century Physics (Cambridge, 2013). He is also co-editor of Quantum Field Theory Lectures of Sidney Coleman (World Scientific, 2018). He was a PhD student of Sidney Coleman, and this book is based in part on his lecture notes from Coleman's course on Relativity. David Derbes received his BA (1974) from Princeton University, Part III of the Mathematical Tripos at the University of Cambridge (1975), and his PhD (1979) from the University of Edinburgh. He was a high school teacher for forty years, winning a Golden Apple in 2007. He has edited Freeman Dyson's Advanced Quantum Mechanics (World Scientific, 2007, 2011), and is co-editor of Lillian Lieber's The Einstein Theory of Relativity (Paul Dry Books, Philadelphia, 2008) and Quantum Field Theory Lectures of Sidney Coleman (World Scientific, 2018). Richard B. Sohn received his BA (1969) and PhD (1976) in Physics from the University of Connecticut, and a Master's in Physics (1971) from the University of Maryland. He has held roles as a professor in physics, a research scientist, and a software engineer. He is co-editor of Quantum Field Theory Lectures of Sidney Coleman, (World Scientific, 2018).