Ordinary chondrites, the most abundant meteorites, constitute about 80% of meteorite falls and are essential to our understanding of cosmochemistry. They provide important information about planetary accretion, the early Solar System, and the geological history of asteroids, including such processes as thermal metamorphism, shock metamorphism, and aqueous alteration. This comprehensive guide begins with meteorite classifications and useful definitions, followed by a discussion of fall phenomena and terrestrial weathering. It provides a detailed overview of the three main ordinary-chondrite groups, which include the most primitive, least-processed meteorites known. Compositional differences among these samples furnish clues to the nature of processes operating in the solar nebula 4.5 billion years ago. These rocks also disclose information on the nature and origin of chondrules, matrix material, and metallic iron-nickel grains. This book is a valuable resource for graduate students and research professionals interested in meteorites and planetary science, as well as amateur meteorite enthusiasts. This comprehensive guide to the most common meteorites facilitates a deeper understanding of asteroids and the early Solar System. Alan E. Rubin is a world-leading expert on meteorites. He is now semi-retired but previously served as an adjunct professor and research geochemist in the Department of Earth, Planetary and Space Sciences at the University of California, Los Angeles. He is a fellow of the Meteoritical Society and winner of the Nininger Meteorite Award and seven Griffith Observer science writing awards. He is the namesake of the garnet mineral rubinite and the main-belt asteroid 6227 Alanrubin. He has published about 220 peer-reviewed papers on the subject, as well as three books, including the well-received Meteorite Mineralogy, published in our Cambridge Planetary Science series in 2021.