Karl Stern was a Catholic psychiatrist in Montreal who published extensively on psychoanalysis and religion from 1951 to 1965. He sent a copy of his second book,The Third Revolution(1954) to Jung, who responded warmly in a (hitherto unpublished) letter dated 30 April 1960. The paper ponders the similarities and differences between Stern and Jung's approach to the psychology of religion, and the impact that Jung's belated response to Stern's book might have had on Stern subsequently.