This paper describes a series of longitudinal experiments which dealt with the development of object awareness in infants, ages 6-18 months. The experiments were designed to document and evaluate Piaget's account of this development. The studies focused on two types of phenomena: (1) when infants first find an object hidden in one place, they will search at that place even when the object has been hidden at a second place; and (2) in terms of a system of levels, infants' responses to seeing one object disappear, and finding another in its place. Examination of the two types of phenomena generally supported Piaget's notion of an intermediate level of object awareness, one where infants sense a definite but diffuse connection between successive appearances of objects in time and space. The need for clarification of Piaget's hypothesis concerning the nature of object awareness during this period is noted. (ED)