This book is an examination of Wittgenstein’s early and late philosophies of logic in relation to accounts of logic and its philosophical significance in early and middle analytic philosophy, with particular reference to Frege, Russell, Carnap, and Strawson. It argues that not only the early but also the later Wittgenstein sought to further develop the logical-philosophical approaches of Frege and Russell. Throughout his career Wittgenstein’s aim was to resolve problems with and address the limitations of Frege’s and Russell’s accounts of logic and their logical methodologies so as to achieve the philosophical progress that originally motivated the logical-philosophical approach. By re-examining the roots and development of analytic philosophy, the book seeks to open up covered-up paths for the further development of analytic philosophy. It explains how Wittgenstein extends logical methodology beyond calculus-based logical methods and how his novel account of the status of logic enables one to do justice to the complexity and richness of language use and thought while retaining rigour and ideals of logic such as simplicity and exactness. The book also outlines the new kind of non-empiricist naturalism developed in Wittgenstein’s later work as well as explaining how Wittgenstein’s account of logic can be used to dissolve the longstanding methodological dispute between the ideal and ordinary language schools of analytic philosophy.