The new experiments underway at the Large Hadron Collider at CERN in Switzerland may significantly change our understanding of elementary particle physics and, indeed, the universe. This textbook provides a cutting-edge introduction to the field, preparing first-year graduate students and advanced undergraduates to understand and work in LHC physics at the dawn of what promises to be an era of experimental and theoretical breakthroughs. Christopher Tully, an active participant in the work at the LHC, explains some of the most recent experiments in the field. But this book, which emerged from a course at Princeton University, also provides a comprehensive understanding of the subject. It explains every elementary particle physics process - whether it concerns nonaccelerator experiments, particle astrophysics, or the description of the early universe - as a gauge interaction coupled to the known building blocks of matter. Designed for a one-semester course that is complementary to a course in quantum field theory, the book gives special attention to high-energy collider physics, and includes a detailed discussion of the state of the search for the Higgs boson. It introduces elementary particle processes relevant to astrophysics, collider physics, and the physics of the early universe. It covers experimental methods, detectors, and measurements. It features a detailed discussion of the Higgs boson search. It includes many challenging exercises. Professors: A supplementary Instructor's Manual is available for this book. It is restricted to teachers using the text in courses.