I Shall Wear Midnight is an Andre Norton Award-winning comic fantasy novel by Terry Pratchett set on the Discworld. It is the fourth novel within the Discworld series to be based on the character of Tiffany Aching. It was published on 2 September 2010 in the United Kingdom, and on 28 September in the United States. It centres on Tiffany Aching, who is now fifteen years old and getting on with the hard work of being a witch. The title is taken from a quotation in A Hat Full of Sky: "When I'm old I shall wear midnight, she'd decided. But for now she'd had enough of darkness."