Edith Nesbit was a fine writer of Edwardian children's books like The Railway Children and The Treasure Seekers. The quasi-metafictional opening paragraph of the latter is worth its place on this thread, I think:

"There are things I must tell before I begin to tell about the treasure-seeking, because I have read books myself, and I know how beastly it is when a story begins, 'Alas!' said Hiledegarde with a deep sigh, 'we must look our last on the ancestral home' — and then someone else says something — and you don't know for pages where the home is, or who Hildegarde is, or anything about it. Our ancestral home is in the Lewisham Road."

Some of J G Farrell's 1970s, adult, novels start similarly by engaging the reader in his act of composition, notably The Singapore Grip: too long to quote here, but worth looking up.

~Michael~