Modern analysts have spent over three decades refining a methodology for single-case-study research that is both appropriate for psychoanalysis and acceptable to the canons of scientific inquiry. This paper suggests that the modern psychoanalytic concept of the contact function is an important contribution to this work. The contact function is a window on the unconscious functioning of the patient in the transference and can therefore be used to ensure that the universe of observation is non-reactive. It also functions as an indicator of closeness or distance to the analyst and so can provide a check on the findings.