This is both a clinical and an epistemological inquiry into the concept of countertransference. A distinction is made between the ordinary countertransference, a transitory disruption residing within the analyst's consciousness, and the extraordinary countertransference, an impasse intolerable to the analyst to such an extent that it remains outside awareness. This distinction, rooted in the history of psychoanalytic thought, is here traced in a recorded psychoanalysis. The clinical material is examined from three perspectives, including empirical evaluation by computer-assisted monitoring of spoken language and two modes of psychoanalytic interpretive listening. Analytic sessions designated as ordinary were readily identified by quantitative measures. However, the threshold between the ordinary and the extraordinary countertransference was reached at the point where empirical observations broke down. Detailed psychoanalytic observation of the four sessions that lie beyond empirical validation led to a formulation of the analyst's state of consciousness during these pivotal hours.