Nils Olof Franzén was a Swedish author who wrote the Agaton Sax series. He was born August 23, 1916, in Oxelösund. He died on February 24, 1997, at age 81.
He was director of programmes for Swedish Radio from 1956 to 1973, and also wrote a number of biographies.
The first of his eleven Agaton Sax books, Agaton Sax klipper till, was published in 1955. According to a description inside Agaton Sax and the Criminal Doubles, Franzén originally wrote the stories for his son.