It has long been known that patients' wishes for cure by analysis give expression to unconscious wishes for instinctual gratification which originate in childhood mental life. Patients sometimes develop theories about how they believe analysis attains its ends; these are likely to affect the way they behave in the analytic situation, and analysis of them may therefore constitute an important contribution to progress in the analysis. Two illustrative cases are presented; in both, the unconscious determinants of the patients' theories turn out to be infantile sexual fantasies connected with their uncon scious wishes for instinctual satisfaction. It is further suggested that analogous unconscious fantasies also influence the theories of analysts and other therapists about how analysis works. In some instances these factors, while not affecting theory formation explicitly, may, without being recognized as doing so, contribute to decisions regarding the modification of analytic technique. Awareness of that possibility may aid analysts in assessing the indications for such proposed modifications.