All of Terry Pratchett’s works make for fantastic reading, but the Tiffany Aching books in particular (of which The Wee Free Men is the first) have a wonderfully strong feminist message.
When trouble threatens her land nine-year-old Tiffany takes it upon herself to act and save the day. For such a seemingly overused setup, the novel approaches it in a way I have not seen elsewhere. Tiffany is pragmatic and her story is not romanticized. She learns harsh lessons about life and is a stronger person for it.
The books read well and easily for adults, and I cannot recommend them enough.