Understanding the analyst's work and its vicissitudes has been a major focus of recent psychoanalytic writing. This study on slips of the analyst represents an attempt to advance our understanding of analytic work. The slips described support the view that slips reflect not simply contributions from instinctual life, but active work-related goals of the analyst in carrying out the analytic tasks. Countertransference is discussed as reflected in the disturbance of intentionality betrayed by the occurrence of a slip. The essential role of the analyst's understanding his or her own reactions is emphasized.