This essential introduction to the philosopher and his thought, combines passages from Wittgenstein with detailed interpretation. Hacker leads us into a world of philosophical investigation in which to smell a rat is ever so much easier than to trap it. Wittgenstein defined humans as language-using creatures. The role of philosophy is to ask questions which reveal the limits and nature of language. Taking the expression, description and observation of pain as examples, Hacker explores the ingenuity with which Wittgenstein identified the rules and set the limits of language.