To become a wizard on the Discworld one has to be the eighth son of an eighth son. Gordo Smith is an eighth son. His eighth child had just been born and has been bequeathed the staff of a dying (then dead) wizard. There's one little problem the wizard did not foresee: Gordo's eighth son, Esk, turns out to be a girl.
Esk, now a little girl, and the staff are given over to the care of Granny Weatherwax, the village's resident witch and magic user. Esk starts to learn witches' magic from Granny; but there is dangerous wizards' magic on the loose, and Granny is at a loss to know how to contain it safely. There is only one solution: Esk must go to the male-only preserve of Unseen University and become the first female wizard (with Granny tagging along as chaperone).
Equal Rites has equality of opportunity for females as its major theme. Granny and Esk come up against the Lore - there is no precedent for female wizards - and the tradition-bound attitudes of the University wizards. Lots of historical inertia there. Will talent prevail over prejudice in the end? If so, how and at what cost?
Pratchett also deals with power and how humans interact with the world. He does this through the exploration of the nature of magic use. Witches tend to nudge the world with their magic to make it a better - or, at least, a less dangerous - place. They borrow rather than own. Wizards, on the other hand, use their magic to dominate and harness the world and its energies. By the end of the book, however, a third and greater kind of magic is discovered.
Equal Rites is the first Discworld novel to feature Granny Weatherwax. Back in 1987, when it was first published, we weren't to know what a deep and intriguing character Granny was to become, but Pratchett had certainly put in the solid foundations on which to build her future character. The book also expands our knowledge of Discworld by filling us in on some of the culture and geography. We are introduced to Headology, the Discworld witches' brand of psychology. Ankh-Morpork is there, albeit with a significantly less perilous complexion, and the river Ankh is yet to come into its full, noisome glory.
On a sadder note, I came across a passage that on hindsight and with knowledge of Terry Pratchett's final illness is quite poignant. Something happens to Esk, and she finds that:
... something was wrong. Her thoughts seemed to be chasing around beyond her control, and disappearing ... Memories dwindled away on the wind. As fast as she could latch on to a thought it evaporated, leaving nothing behind. She was losing chunks of herself, and she couldn't remember what she was losing.
All up, Equal Rites is a nifty little fantasy novel in itself. It can be read without reference to the rest of the amazing Discworld series and not suffer too much harm. Of course, it is that little bit better for being part of the series. And the best is yet to come. Oh, yes!