"On the Parts of Animals" is a biological treatise written by Aristotle, in which he extensively examines the anatomy and physiology of different animals, including humans. The book is divided into four sections, each focusing on a different aspect of animal life. In the first section, Aristotle explores the concept of soul and distinguishes between different types of souls that exist in animals. In the second section, he discusses the structure and function of sensory organs, such as eyes and ears, and how animals use them to interact with their environment. In the third section, he analyzes the digestive system and other internal organs, as well as the reproductive system, to understand how animals sustain themselves and reproduce. Finally, in the fourth section, he looks at the differences between different animal species and the variations in their anatomy and physiology. Read in English, unabridged.