Our Mr. Sun examines the Sun and how it works, the Sun's profound influence on life on Earth, and the possibilities for harnessing sunlight for solar electricity; solar cells had been demonstrated at Bell Laboratories in 1954 during the development of the film. For the screenplay, Capra first contracted for treatments by two prominent authors, Aldous Huxley and Willy Ley. Ultimately, Capra wrote the screenplay himself, subject to approval by a scientific advisory board put together by N. W. Ayer. The principal scientific source used for the screenplay was the book Our Sun (1949) by Donald Menzel, who also consulted with Capra about the screenplay. Menzel opposed most of the religious elements of Capra's screenplay, but many were included in the version that was produced.