Lettau never used his middle name, Adolf, if he could avoid it. He gave incendiary speeches at the Freie Universität Berlin denouncing the Springer Press and was thereupon expelled from West Germany because he was a foreigner—he carried an American passport and emigrated to the US in the middle of the 1950s, and was a professor of German Literature at the University of California, San Diego from 1967. He received the War Blind Prize for radio plays in 1979, the Berlin Literature Prize in 1993, and the Bremen Literature Prize in 1995. He took early retirement in 1991 because of health problems. In 1996 he traveled to Karlsruhe for the 90th birthday of his mother where she was hospitalized after a fall. Lettau died there of pneumonia, June 17, 1996.