This paper deals with the fundamental elements of the Tractarian metaphysics: its language, basic categories and the program of complete analyses. The issue of complete analyses seems to play a principal role. The author tries to prove that the complete analyses proposed by Wittgenstein is possible only in the case of limited number of propositions. However, the use of fundamental expressions of metaphysics such as thing, complex, fact and world deserves detailed examination. For Wittgenstein, these expressions signify formal concepts and the very existence of formal concepts is what makes metaphysics (not only in the Tractatus) possible.