The "Tractatus Logico-Philosophicus" is a philosophical work by Ludwig Wittgenstein, published in 1921. It explores the relationship between language, reality, and thought, proposing that the structure of language mirrors the structure of reality. Wittgenstein argues that meaningful statements can only be made about facts that can be depicted in logical form. The text is organized into a series of numbered propositions, culminating in the idea that many philosophical problems arise from misunderstandings of language. Wittgenstein concludes that what can be said clearly can be expressed in language, while what cannot be said should be passed over in silence.