In 1918 Russell gave a series of lectures in London with the title “Logical Atomism.” He glowingly praised Wittgenstein, writing that the lectures

Russell was eager to launch his new program for philosophy as the science of logical form and to introduce Wittgenstein. But in his efforts to establish a reputation for Wittgenstein, he embellished matters greatly. Wittgenstein's ideas were at a very immature stage during his conversations with Russell between 1912 and 1914, and his studies on logic in Norway were poorly developed. Wittgenstein's “Notes Dictated to G. E. Moore in Norway” (dated April 1914) did not reach Russell until April 1915. The war intervened, and Russell lost contact with Wittgenstein. He did not hear of him again until June 1919.

When Russell finally did get news, he found that Wittgenstein had managed to write a book while in the Austrian army. With the war at an end, Wittgenstein wrote a letter to Russell from an Italian prison camp in Cassino.