Because memory enters into virtually all cognition, it is impossible to design cognitive models that view memory as a self-contained cognitive faculty. Instead, memory researchers focus on specific aspects of memory. Taking this regional approach to memory, the chapters of this volume evaluate models of the short-term retention of knowledge, conceptual knowledge, autobiographical knowledge, transitory mental representations, the neurobiological basis of memory, and age-related changes in human memory. At the center of each chapter is a concern with the problem of representation--how the mind represents reality and, in the case of memory, how experience is represented, retained, and reconstructed. The authors evaluate the models against empirical findings and against current knowledge about brain function and architecture. They also address the relationship between formal and nonformal models of human memory.