Wittgenstein said, 'really one should write philosophy only as one writes a poem'. This Element provides a comprehensive explanation of what he possibly meant by the statement, and why the statement is a correct description of Wittgenstein's philosophy. It connects the statement with Wittgenstein's idea of philosophical clarification, the methods he uses in it and the masters he acknowledges as the sources for his ways of 'moving his thought'. The Element introduces distinctions that are essential for approaching the multilayered complex of Wittgenstein's oeuvre. One is the distinction between writing philosophical clarifications for himself on the one hand and forming philosophical books for his reader on the other. While poetry was central to both activities, it was mandatory for the second. Indeed, for creating the perfect philosophical book, Wittgenstein thought he lacked precisely what some of his masters possessed: poetic genius.