How does a child learn to think about the world, to use mathematical reasoning, to master the syntactic structure of language or the alphabetic structure of text? These issues are addressed by John McShane within an information processing framework. The central components of this framework are the innate cognitive architecture and mechanisms of learning, and the procedures and representations that are created from information processing. The topics considered include perceptual development, the development of symbolic representations, concepts and categorization, memory development, reasoning about number and quantity, language development and the development of basic reading skills. For each topic methodological issues are discussed and the empirical evidence is reviewed.