A high-level, rigorous, and technical treatment of modern particle physics, this book was written by a well-known professor at Harvard University who conducts ongoing research programs in several areas of theoretical particle physics. Introductory chapters examine Noether's theorem, the electron, and SU (3) quark models. Subsequent chapters explore weak decays of light hadrons, effective low-momentum field theories, the transformation law for baryons, mode counting, effective field theories, and the renormalization group. Two helpful indexes review dimensional regularization and background field gauge. In addition to its value as a text for advanced undergraduate and graduate students of physics, this volume also serves as a reference for professionals.