Anthony G Williams
Greybeard
I'd like to put in a word for this one. Pretty well straight SF, with an engaging heroine, an unusual plot, and a light and amusing touch. An easy, feel-good sort of read. It's still hanging on to its place on my bookshelves after over 35 years - in fact, I think it'll soon be time to read it again, to see if it lives up to my memory of it!