Janwillem Lincoln van de Wetering was the author of a number of works in English and Dutch. He was particularly noted for his detective fiction, his most popular creations being Grijpstra and de Gier, a pair of Amsterdam police officers who figure in a lengthy series of novels and short stories. Most of the mysteries are rich with images from Amsterdam, where most of them take place; some also feature a cat named Oliver. He also wrote stories for children and nonfiction works. He usually wrote in Dutch and then in English; the two versions often differ considerably.