This paper, the last to be published by Martha Harris, takes a historical overview of certain key moments in the evolution of Kleinian thinking. These are: Klein's extension of Freud's “projection” into “projective identification” as a result of her observation of children's phantasy worlds; work by her colleagues and students with psychotic adults and by Meltzer on sexual theory, enabling a clear differentiation between narcissistic and object-related modes of mental operation in forming personality structure; Bion's extension of “projective identification” and of Klein's “epistemophilic instinct” in his theory of thinking; and Bick's perception of skin functioning in infants which, together with her colleagues' and students' work on autism, enabled a differentiation between two-and three-dimensional states of mind. These apparently different or differently-derived theories integrate into a single model of personality growth. The examples that follow on however emphasize the fact that individuality is varied and surprising and does not necessarily conform to the expectations aroused by any existing model.