His first commercially successful novel, Kun isoisä Suomeen hiihti [When Grandfather Skied to Finland], a humorous description of Katz's family history and Finland's entry into World War II, has been translated into nine languages, while his novel Saksalainen sikakoira [Schweinehund], offering insight into the causes of the Holocaust and the rebirth of fascism, is available in six languages. He lives in Loviisa, Finland.