This Element presents a concise and accessible view of the central arguments of Wittgenstein's Tractatus Logico-Philosophicus. Starting from the difficulties found in historical and current debates, drawing on the background of Russell's philosophy, and grounded in the ladder structure expressed in the numbering system of the book, this Element presents the central arguments of the Tractatus in three lines of thought. The first concerns the role of the so-called 'ontology' and its relationship to the method of the Tractatus and its logical symbolism, which displays the formal essence of language and world. The second deals with the symbolic unity of language and its role in the 'ladder structure' and explains how and why the book is not self-defeating. The third elucidates Wittgenstein's claim to have solved in essentials all philosophical problems, whose very formulation, he says, rests on misunderstandings.