This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book discusses "Wittgenstein the phenomenologist" and "Wittgenstein the verificationist", describing them as interrelated yet short-lived figures in Wittgenstein's development. It seeks to show how both Wittgenstein and Levinas regard the self and the world as interdependent, and insist that ethics arises from the relationship between the two. The book discusses the problem of whether self-consciousness can be understood as consciousness of one's self, as many modern and contemporary philosophers maintain. It argues that there is a genuine logic pertaining to grief, a logic of process and of paradox. The book identifies in Cartesian dualism a common target of middle Wittgenstein and early Merleau-Ponty. It presents Wittgenstein's and Heidegger's conceptions of the task of philosophy as putting forward, in both their early and later phases, clarificatory reminders as opposed to factual claims.