Jef Geeraerts (Jozef Adriaan Anna Geeraerts, 23 February 1930 - 11 May 2015) was a Belgian writer. He was born in Antwerp. He decided to become a writer. He went to the University of Brussels to study Germanic languages. He was known for his books "Gangreen 1" ("Black Venus"), "Gangreen 2" ("De Goede Moordenaar"), "Gangreen 3" ("Het Teken van de Hond") and "Gangreen 4" ("Het Zevende Zegel").