The Tractatus Logico-Philosophicus is a book written in the early 1900s by Austrian Philosopher Ludwig Wittgenstein. In the book, he tries to explain how our language works and how it's related to reality. He believes that our language is not very accurate because words can only ever point at things and not explain them fully. Much of the book is focused on how to talk about the things around us without being completely wrong. He talks about how certain things (like ethics and morality) can't really be expressed with words, since the complexity of these things can never be fully expressed.