This is a collection of my papers on the history and philosophy of logic and mathematics published for the last thirty years. Virtually all the chapters tackle some particular logical, methodological, epistemological, and ontological issues that are not entirely clear in official history of modern logic. In retrospect, there were some very good reasons for me to be fascinated by the particular issues and the philosophers at the earlier stages of my research. Topically speaking, these chapters can be grouped under four parts. Part 1, which deals with Gottlob Frege, was motivated to understand what aspects of his logic were truly innovative in its revolution against the Aristotelian logic. Part 2 treats Hilbert and his associates and followers in the hope to understand the revolutionary change in the axiomatic method.