This thesis discusses normal principles of infant development during the first 2 to 3 months of life and applies these principles to the provision of services to drug-exposed infants. Emphasis is on the infant as an active and interactive participant in his/her own development, the primacy of the body during this early developmental period, and the interrelatedness of physical experience and emotional development. Chapter 1 examines underlying assumptions of the infant's basic nature. Cultural assumptions are discussed as is the infant's capacity for subjective experience. Chapter 2 outlines key principles and processes of normal development and provides information on neurobehavioral organization and the organizational model. Chapter 3 evaluates the emotional development and subjective experience of the infant. The infant's achievement of basic trust, ego integration, and the "coming into being" of the infant's true self is discussed. Chapter 4 provides information on the medical and neurobehavioral effects of intrauterine drug exposure. Also discussed is how various environmental variables impact development of hospitalized infants. Chapter 5 describes a hospital-based early intervention program which stressed that effective clinical interventions with very young drug-exposed infants should be based on normal development. (Contains over 100 references.) (Author/CR)