Introduction -- The common hellenic meaning of "genus" -- The Pollaxos legomena or things said in many ways -- Genus in the explanation of change : the subject and substratum principles -- To what is Aristotle's theory of change a response? : the pre-socratic and platonic background -- Change : the principles of nature in physics I -- A first mention of matter and form -- Genus in the explanation of change : the definition of change -- Aristotle's definition of (...) change : physics III -- The circularity objections -- The advantages of Aristotle's theory -- The use of genus in change -- Genus in the explanation of change generation, "for man begets man" (1032-24) -- Generation -- Change and genus -- The generation of animals as organic substances -- Animal generation and the mule -- Genus in definitions : the Aristotelian and platonic division of a genus -- "What is definition?" -- Platonic division and definition -- Aristotle's use of genus and animal taxonomy -- The use of "genus" in Pa I -- Analogy vs. the more and the less -- Taxonomy : the megista gene -- Genus in definitions : why Aristotle was a realist -- Division and definition in Aristotle -- Causal definitions , substantial definitions, and definitions by matter and form -- The unity of definition and division -- The use of genus in definition -- Case study I : the definition of the psyche -- On matter as substratum -- On matter : the domain problem -- On matter : is it substance? -- On matter : potentiality -- The elements : is ontological reduction possible? -- Proper matter and generation revisited -- The indeterminacy vs. nature problem -- On genus as matter -- The analogy interpretation : Aristotle's mention of genus as matter -- The literal interpretation : Aristotle's use of genus as matter -- The principal unity of Aristotle's thought. (shrink)