Just when I thought I had read all the Diskworld novels I found an unread one on my shelf.
I must have bought it a long time ago and intended to read it later, it really was unread, the spine unmarked and the pages undogged.
Sadly the cover art is as subtle as a brick:
but I guess many of the intended audience would other wise miss the literary reference.
© 1990 Terry and Lyn Pratchett
This edition 200 Millennium - Gollanz