The whole discworld series is such a fun read. An adventurous romp through an impossible world. It's lighthearted, but engaging enough to keep you reading at night long after you should have turned out the light!
This is my favorite book of all time, through my travels it comes with me. Terry Pratchett does a great job of getting you to question the gender equality issues.
As you may know, Terry Pratchett tends to write his Discworld novels about groups of characters. This one features Granny Weatherwax and some of the (Pre-Ridcully) Unseen University characters.
The first time I read this book, I enjoyed it, but wasn't terribly impressed. (Bear in mind, I tend to prefer the books about the City Watch or Death.) But yesterday when I re-read it, I found myself snickering and chortling quite a bit.
This tale explores the magic theory of Discworld, i.e., how the magic of Wizzards and Witches is different. It also shines a bit of light on Granny Weatherwax's past, so if you like that character (I do.), then I highly recommend it. Also, if you happen to hang around with Neo-Pagans (in real life) I think you'd find it particularly hilarious.