Re: I'm touched by the weirdness of this request...
"I wouldn't start with Unseen Academicals or Raising Steam, two of the last Discworld series as I'm not sure they are as good as the others. Felt like he was losing his bite, particularly in Raising Steam *ducks and runs for cover*"
Personally I'd add "Strata" to that (happily, very) short list - vaguely Disc World related and an attempt to explain how Disc World came into being, but it doesn't really fit with the rest of the series.
Biting the hand that feeds IT
