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.