That is the title of a new book by Anthony Gottlieb on the life and ideas of the great but perplexing 20th-century philosopher Ludwig Wittgenstein. Right now, I am on Chapter 3, which is titled “The teacher who taught himself.” Chapter 1 (“‘A new way of philosophizing'”) explains why Wittgenstein is worth studying, while Chapter 2 (“At home with the Wittgensteins”) surveys Wittgenstein’s Viennese background and family history. I will report back soon.