Advertisements stated "The Discworld has come of age"
Jingo is a novel by Terry Pratchett, one of his phenomenally popular "Discworld" series. It was published in 1997. In this story Pratchett comments on the jingoistic nature of people, the desire to attack others for perceived ills to mask your own.
The book deals with a war between Ankh-Morpork and Klatch, over a new island.