Origin of the essays. Introduction. 1. On Aristotle's notion of existence. 2. Semantical games, the alleged ambiguity of `is', and Aristotelian categories. 3. Aristotle's theory of thinking and its consequences for his methodology. 4. On the role of modality in Aristotle's metaphysics. 5. On the ingredients of an Aristotelian science. 6. Aristotelian axiomatics and geometrical axiomatics. 7. Aristotelian induction. 8. (with Ilpo Halonen) Aristotelian explanations. 9. Aristotle's incontinent logician. 10. On the development of Aristotle's ideas of scientific method and the structure of science. 11. What was Aristotle doing in his early logic, anyway?: A reply to Woods and Hansen. 12. Concepts of scientific method from Aristotle to Newton. 13. The fallacy of fallacies. 14. Socratic questioning, logic, and rhetoric.