The concept of mentalisation (Fonagy et al. 1991) has been used to describe the way in which the child’s ability to understand his own and others’ minds crucially depends on the developmental opportunity to recognize himself as represented in the mind of another. Within the context of a case presented for supervision, this paper discusses the importance of mentalisation or ‘reflective function’ in the development of the psychological self, drawing on recent attachment-related research. Peter Webber’s film ‘Girl with a Pearl Earring’ is also presented and discussed as illustration of the psychotherapeutic significance of searching for the individual’s inner psychological potential. © 2005, Taylor & Francis. This is an author produced version of a paper published in Psychodynamic Practice, uploaded in accordance with the publisher’s self- archiving policy. The final published version (version of record) is available online at the link below. Some minor differences between this version and the final published version may remain. We suggest you refer to the final published version should you wish to cite from it.