This paper reviews the development of Infant Observation from its inception in 1948. It revisits Bick's original 1964 paper and explores current divergences from her original practice in the context of contemporary theories of psychoanalysis and adjacent disciplines and of relevant changes in society. It draws on the personal recollections of Bick's early students as well as the expanding published literature. It discusses seminar technique, the training of seminar leaders, and clinical and research applications of the observational method. [Margaret Rustin]