How do animals represent space, time, number and rate? From insects to humans, Charles Gallistel explores the sophisticated computations performed in these ubiquitous yet neglected domains of animal learning. He proposes new and imaginative hypotheses about brain and mental processes and provides original insights about animal behavior using a computational-representational framework that is an exciting alternative to traditional associative theories of learning. Gallistel argues compellingly that experimental psychologists should begin to view the phenomena of learning within a framework that utilizes as the proper unit of analysis the computation and storage of a quantity, rather than the formation of an association that has been the basis of traditional learning theory.