Subjects covered in this, the third and last, volume of translation of this work include: why the elements are four in number; what's wrong with Empedocles' theory of elements; how homogeneous stuffs, particularly the tissues of a living body, come to be and consist of the elements. The volume also contains very important discussions of causes, particularly of efficient cause, and of necessity in the sphere of generation and corruption. It will be of interest to the students of ancient philosophy and science (the commentary draws on earlier philosophical and medical texts); of Patristics and Christian Theology (it allows comparison of Philoponus' later creationist doctrine with his earlier ideas about generation); of medieval philosophy (this text was known to the Arabs; it is used by Avicenna and Averroes); and to anyone with interest in the metaphysics of causation, emergence, necessity and determinism.