Volume 1 of the three-volume revision of the 1959 edition of the Trilobita. Contains introductory chapters on the morphology of the exoskeleton; the trilobite body; mode of life, habits, and occurrence; use of numerical and cladistic methods; ontogeny; evolutionary history; classification; and glossary. In addition, the volume includes a systematic description for the orders Agnostida and Redlichiida, an extensive correlation chart for the Cambrian, and explanatory notes.