Throughout the 1920s and 1930s, Reck was also a novelist, mainly of children's adventure stories. One book, "Bomben auf Monte Carlo", has been filmed four times. Many of his books were banned by the Nazis, and more were not published until years after his death. Today his best-known work is Diary of a Man in Despair ("Tagebuch eines Verzweifelten"), his journal of life under Nazi rule (which he vehemently opposed). It was published for the first time in 1947, then republished in 1970 in English translation by Paul Rubens.