Aristotle's Parts of Animals is a foundational text in both the history of philosophy and the history and philosophy of biology. Critically important for understanding his mature philosophical programme, the Parts of Animals has two chief aims. PA Book I is an introduction to the study of animals and plants and provides preliminary considerations for how to investigate all aspects of their nature. PA Books II-IV is the most comprehensive example of the application of Aristotle's philosophical methodology to real world examples of substances, that is, to animals. In this book, a team of international experts cover topics such as Aristotle's exhortation to study biology, his methodology in the study of natural entities and kinds, the study of mind as part of nature, his analysis and use of concepts such as essence, substance, definition, matter, form, species, analogy and teleology, and the influence and legacy of the text.