Austrian

 A popular lecture given, it is believed, in Cambridge to the society known as “The Heretics” in 1929 or 1930.

"Tractatus Logico-Philosophicus is the only book-length work published by Austrian philosopher Ludwig Wittgenstein in his lifetime. He wrote it while a soldier on leave during World War I in 1918. First published in German in 1921 as Logisch-Philosophische Abhandlung, it is now widely considered one of the most important philosophical works of the twentieth century. The Latin title was originally suggested by G. E. Moore, and is a homage to Tractatus Theologico-Politicus by Benedictus Spinoza. The reason for Wittgenstein's "notorious" literary style—his utterly sober and succinct manner of expressing himself—has generated much speculation by commentators. Though Wittgenstein in later writings sharply differed with the philosophical ideas he expressed in the Tractatus, he retained the basic writing style—short sentences or paragraphs rather than narrative exposition in all of his writings."