Equal Rites (Discworld)

Equal Rites is the third in Terry Pratchett's phenomenally successful Discworld series. The last thing the wizard Drum Billet did, before Death laid a bony hand on his shoulder, was to pass on his staff of power to the eighth son of an eighth son. Unfortunately for his colleagues the eighth son turns out to be a daughter, and women aren't supposed to be wizards. Eskarina inherits the wizard's staff and with the reluctant help of Granny Weatherwax sets out to learn her new calling.