This paper makes use of a clinical vignette from the therapy of a 13-year-old boy to explore the concept of projective identification. After presenting a session in which there was a particularly difficult enactment between the boy and his therapist, the paper asks how the ‘public face’ of our psychoanalytic theories relates to the ‘private face’ of our moment-to-moment responses in a clinical situation, and explores this question further by looking at the concept of projective identification. After a brief survey of the historical development of the term, focusing especially on Klein and Bion, the clinical material is re-examined. The paper ends by reviewing contemporary Freudian perspectives on projective identification, including the work of Joseph Sandler, and suggests that we may discover the value of theoretical concepts by exploring how they enable us to think and respond differently in the clinical situation.