A System of Logic, Ratiocinative and Inductive, Eighth Ed‪.‬

This book was John Stuart Mill's first published book-length work of philosophy. Mill was fed up with the wishy-washy use of logic in England in his day, and wanted to create a rigorous, systematic approach to thinking that could stand up to the stresses of the dawning scientific age. In this book, Mill surveys the history of logical reasoning and then proposes five principles of inductive reasoning that, in time, have come to be known as "Mill's Methods." While many other thinkers of his day considered logic to be governed by some internal, sixth-sense process, Mill's Methods created a empirical, observation-based system of thought and reasoning.