Book: Artificial Intelligence on the Sinclair QL - Make your micro think, by Keith and Steven Brain
http://www.amazon.co.uk/Artificial-Inte ... 884&sr=1-7
I have a copy here in reasonable condition, good spine, slightly curled corners, for £7.50 including shipping to the EU.
It's not an especially enlightening book, but it does discuss the general concepts of decision making, expert systems and fuzzy logic, with SuperBASIC code examples. More interesting for the novelty value that I haven't seen many copies come up for sale, and your collection is incomplete without it.