Wilhelm Stekel (German: ['Ste:k@l]; 18 March 1868 - 25 June 1940) was an Austrian physician and psychologist, who became one of Sigmund Freud's earliest followers, and was once described as "Freud's most distinguished pupil". According to Ernest Jones, "Stekel may be accorded the honour, together with Freud, of having founded the first psycho-analytic society"; while he also described him as "a naturally gifted psychologist with an unusual flair for detecting repressed material." He later had a falling-out with Freud, who announced in November 1912 that "Stekel is going his own way". His works are translated and published in many languages.
Contributions to the theory of fetishism and of perversion
Stekel contrasted what he called "normal fetishes" from extreme interests: "They become pathological only when they have pushed the whole love object into the background and themselves appropriate the function of a love object, e.g., when a lover satisfies himself with the possession of a woman's shoe and considers the woman herself as secondary or even disturbing and superfluous (p. 3). Stekel also deals differently than Freud with the problem of perversion. A lot of perversions are defense mechanisms (Schutzbauten) of the moral "self"; they represent hidden forms of asceticism. To Freud, the primal sexual venting meant health, while neuroses were created because of repressing sexual drives. Stekel, on the other hand, points out the significance of the repressed religious "self" in neuroses and indicates that apart from the repressed sexuality type, there is also a repressed morality type. This type is created in the conditions of sexual licentiousness while being opposed to doing it at the same time. In the latter instance, 'Stekel holds that fetichism is the patient's unconscious religion'. "Normal" fetishes for Stekel contributed more broadly to choice of lifestyle: thus "choice of vocation was actually an attempt to solve mental conflicts through the displacement of them", so that doctors for Stekel were "voyeurs who have transferred their original sexual current into the art of diagnosis".  Complaining of Freud's tendency to indiscretion, Ernest Jones wrote that he had told him "the nature of Stekel's sexual perversion, which he should not have and which I have never repeated to anyone". Stekel's "elaboration of the idea that everyone, and in particular every neurotic, has a peculiar form of sexual gratification which is alone adequate" may thus have been grounded in personal experience.  On sado-masochism, "Stekel has described the essence of the sadomasochistic act to be humiliation".

Q: what was his contribution to the theory?
A: Stekel contrasted what he called "normal fetishes" from extreme interests:
did he work with anyone on the theory?
unknown
unknown