The third in a series of three booklets intended for parents of young handicapped children addresses cognition. The development of cognition is discussed and milestones charted from birth to age five. Learning processes are enumerated (using the senses, attending, exploring, adapting, imitating, and asking questions). Suggestions are given for parents to help their children develop cognitive skills through sensory experiences, building on past experiences, observing behavior, encouraging practice, and communicating with teachers and therapists. Ideas and activities are presented for making the home responsive and stimulating for infants, toddlers, and preschoolers. Examples of two young children are cited to illustrate ways in which parents can help their children develop cognitive skills. (CL)