this treatise provides a systematic overview of the concepts Galen will be addressing, particularly the distinction between the roles of the soul and nature in organismal functions. He begins by categorizing the actions and effects of living things, distinguishing between growth and nutrition, which are common to both plants and animals. The text sets the stage for a deeper analysis of specific processes, such as digestion and blood-making, laying out Galen's intent to explore the faculties responsible for these biological phenomena while responding to philosophical debates regarding physical existence and change. This introduction emphasizes the importance of clear definitions and systematic inquiry, marking Galen's work as a significant contribution to the medical and philosophical knowledge of his time. (This is an automatically generated summary.)