This series of books presents the fundamentals of logic in a style accessible to both students and scholars. The text of each essay presents a story, the main line of development of the ideas, while the notes and appendices place the research within a larger scholarly context. The basic theme here is the analysis of formal logic in terms of what metaphysical assumptions we need when we develop the formal systems we use. The essays together give a perspective of formal logic as part of the art of reasoning well.