Exposing the myth of "the two Wittgensteins, " this book provides a detailed account of the unity in Wittgenstein's thought from the Tractatus to the Philosophical Investigations. Unlike recent interpretations in the literature, this account is not the story of the unfolding of a single view, but instead the story of an ongoing conversation and its internal logic. Throughout his career, Wittgenstein argued that philosophical problems about the necessary and the impossible, on the one hand, and about the meaningful and the nonsensical, on the other, might be dissolved by means of an elucidation of ordinary language use. This approach always relied on the same strategy, namely contextualism. He identified decontextualization as the main source of philosophical confusion and argued that philosophical understanding consists of situating concepts in the normative contexts in which they function.