If you never had a copy of Tin Woodman, you didn't "forget" Mrs. Yoop, because that was the only book she showed up in; if you didn't read Tin Woodman, you never met her.

That's true, but in my case, I checked the book out of the library a number of times, so I knew the story. I just didn't know it as thoroughly as the books I had at home and read overandoverandover again.