It is sad that Rincewind was sort of shunted to one side, he was so gloriously human, inept and incompetent but still muddled through with the awesome luggage. As a Robert Heinlen fan, one of his books "Glory Road" has a divine box just like the TARDIS little on the outside and huge inside, my dream handbag incidentally.
I have never heard of Tom Holt, will check up on him, ta for the heads up.
