John Stuart Mill"s "System of Logic, Ratiocinative and Inductive" was a ground-breaking and highly influential work of philosophy, first published in 1843. Mill espoused the empiricist view of political and social philosophy, and formulated the five principles of inductive reasoning that are now known as Mill"s Methods. The two original volumes of the seventh edition have here been brought together into a single book, which has been carefully edited to be clear and readable.