The third entry in my Great Terry Pratchett Re-read-athon is where I belatedly caught on. As I recall, it was a review in a magazine in 1987 that led me to this book, which comes at the Discworld from another angle. This is where we first meet Granny Weatherwax, a witch who has more power than she generally lets on, knowing that the real secret of magic is knowing when not to use it, and that convincing people to do what they need to (headology), whether that’s get well, or to not be evil, is far more useful.
The story concerns the power of magic itself, and how it can be passed on. Drum Billet, an old wizard, knowing (as all magical types get to know) that death, and indeed Death, is approaching, passes on his staff to the newly born eighth son of an eighth son. Eight being a particularly magical number on the Disc, all such men are destined to be wizards. And for reasons of, errr, reasons, only men get to be wizards. Which makes it a wee bit awkward when it turns out that the baby in question is rather more of a girl than a boy. Well, completely a girl called Esk, as it happens.
Esk turns out to have wild magical power, which is far too dangerous to be let loose without training, and so Granny Weatherwax agrees to take Esk to Unseen University, where she is, of course rejected on grounds of insufficient maleness.
Also arriving at Unseen University that day is Simon, a boy with magical powers and interesting theories of the kind that make perfect sense while they’re being explained, but sort of fade away afterwards.
Fun follows when it turns out that creatures from the Dungeon Dimensions are attempting to use Simon as a gateway into the physical world, which would be a Very Bad Thing indeed. While Granny Weatherwax and the Archchancellor of Unseen University have a nice chat, Bad Things are happening.
Can Esk and Simon escape from wherever their minds have gone? Can the Discworld be saved from the ravages of the things from places it’s best not to think about? Was this really the third book in a trilogy? Well, you’ll just have to read it to get the full story, won’t you?
It was more or less at this point that a subtle change became apparent. While the books are set on a quite fantastical planet, where there’s magic, occasional dragons (provided you can believe in them and there’s a strong enough magical field) and all that kind of thing, this is beginning to be just a backdrop for stories. Stories about people. And while there are always lots of laughs (puns even I wouldn’t attempt, jokes of all kinds), serious ideas are beginning to creep in. As John Clute mentioned in a review of a Discworld book, Terry is writing comedies, and comedy is a serious business.
 I forget which one, it was a while ago