Unc, If you want to read the discworld books I would recommend you start with Guards Guards. The guards in question are at least human, slightly scruffy misfits, and not too efficient, but human. The discworld is inhabited by Dwarves, Trolls, Gnomes, etc, but the story lines are very like those in any of the cop shows we get here on 'Earth'. You do need to have a whacky sense of humour to enjoy them. Tiffant Aching, by the way is an apprentice witch. Terry wrote four books about Tiffany, I would never part with them.
I note that Fife Libraries has a volume with the first two books in it (about "Rincewind") and one copy somewhere (and if still available) of Guards Guards. I might give them a quick look to see f I can get into them.