In this foundational paper, Esther Bick describes the nature and purpose of infant observation seminars, and the technical and emotional difficulties faced by the observer in relation to the family and the seminar group. Several examples are given, including long extracts from an observation of one particular baby, in order to demonstrate how only close attention to detail can make these primal emotional strains observable and illuminate the experience of the observer, and of the mother and baby couple. She also stresses the importance of consecutive observation for gathering scientific data as free as possible from linguistic preconceptions. She concludes that the psychoanalytic validity of the experience lies partly in learning how to observe, and partly in the prototypal relationship to the breast as part-object as being the “basic unit of relationship from which more complex relationships are built”.