Conversation so far:
What was Wilhelm Stekel's contribution to the psychoanalytic theory?
Stekel wrote one of a set of three early Psychoanalytic studies of psychical impotence referred to approvingly by Freud: Freud had written a preface to Stekel's book.

Question: Did he work with anyone on the theory?
Self-contained rewrite: Did Wilhelm Stekel work with anyone on the theory of physical impotence?