imaginary companions

NarratorLady was writing about Miss Hargreaves by Frank Baker where the protagonist creates a ficticious person, and she comes to life. It reminded me of Bumbridge Bunbury in The Importance of Being Earnest, and is now on my wishlist. My public library informs me there is a subgenre for imaginary companions, and I wonder if this is a more widespread trope than I knew.

I can't think of any books I've read in which there was an imaginary companion, but I might just be forgetting.

Aha! It's on my TBR shelf. Don Quiote imagines the existence of Friston the magician (El Sabio Frestón), who allegedly steals his books and enchants windmills.

I can't think of any at the moment, either. The Importance of Being Earnest is one that I loved on film! I have two versions of it and saw the play not too long ago. Love it!

Harvey?

Of course!!! I hadn't thought of its being in print form, and I wasn't sure of the date.

Well, the movie was 1950, so the play has to be older.

Miss Hargreaves came yesterday, so of course I had to dip in a little bit. I'm not sure I'll read the whole thing - it gets a bit repetitive, and definitely takes a darker more serious turn in places. Some of the writing sparkles, and I've added a couple of quotes on the works page.
It's got an interesting reflection on 'creation' and the impossibility of un-doing it.

I found Miss Hargreaves intriguing, but not warming. I had expected something cozier and it really wasn't. But you are quite right that the whole point is about the artist's inability to un-make a creation. I kept thinking of Arthur Conan Doyle and his desire to kill off Sherlock Holmes.