Given what is known about cognitive development, how well prepared are 4-year-old children to succeed in school? This paper addresses the question by describing three areas in cognitive development, highlighting major themes in the research, and suggesting implications for teaching practice and social policy. Classical and contemporary views of cognition are contrasted prior to discussions of theory contextualizing and differentiating cognitive development. Qualitative and, preponderantly, quantitative evidence for the "five-to-seven shift" is reviewed. Discussion concludes by contrasting academic versus everyday cognition. It is argued that teaching and assessing 4-year-olds in public school settings will fail, unless special emphasis is placed on embedding cognition in everyday practical terms, so that all classroom communications "make human sense." It is concluded that a considerable amount of information is available concerning the cognitive development of young children which can serve as a guide in teaching practice and social policy. Because young children do have an intrinsic motivation to learn and to understand, they deserve developmentally appropriate educational challenges. The alternative relegates 4-year-olds to understimulation. (RH)