Robertson Davies (1913–1995) Canadian journalist, playwright, professor, critic, and novelist
From a letter published in The Merry Heart : Reflections on Reading Writing, and the World of Books (1996).
Context: To ask an author who hopes to be a serious writer if his work is autobiographical is like asking a spider where he buys his thread. The spider gets his thread right out of his own guts, and that is where the author gets his writing.