What computations do our brains perform when we complete a simple addition task such as adding two and three to make five? How do numerical abilities develop through infancy? Is language a prerequisite for numeracy, or can animals as well as human beings calculate with numbers? Ever since Plato, the mental representation of number and the psychological and neurobiological bases of mathematical abilities in general have been the focus of philosophical and scientific speculation. Recently, new methods in cognitive and developmental psychology, neuropsychology, and animal behavior research have permitted the experimental exploration of old questions. Numerical Cognition constitutes the first comprehensive and up-to-date overview of an emerging field, and points out future directions for researchers to take. An introductory chapter offers an overview of the problem and then focuses on the critical relationship between number and language and on evidence for nonlinguistic representations of number. Subsequent chapters trace the fascinating parallels between human and animal representations of number, probe the meanings of the disintegration of numerical abilities following brain damage, and analyze unusual forms of visuo-spatial number representations first discovered by Sir John Galton more than a century ago. The editor and authors of Numerical Cognition have performed a signal service for students and researchers in cognitive science, neuropsychology, and mathematics, indeed, for everyone interested in the nature of mathematics and its relation to mind and brain.