This book provides a comprehensive treatment of the history and implications of the notion of multiple memory systems, of the evidence that supports it, and of the nature of the systems discovered so far. The book begins by highlighting a brief history of ideas about multiple memory systems and how those ideas fit into the story of the progression of our understanding of the nature and organization of memory in the brain. Other early chapters address some of the themes and principles that are common to all memory systems, including the fundamentals of cellular plasticity and the critical role of the cerebral cortex in memory. The central portion of the book then attempts to characterize the role of several specific memory systems, starting with a detailed analysis of the hippocampal memory system - the brain system that mediates declarative memory, our ability to recollect consciously everyday facts and experiences, by supporting the capacity for relational memory processing. Individual chapters focus on non-human primate and rodent models of amnesia, on hippocampal neuronal activity, and on the permanent consolidation of declarative memories. Subsequent chapters present evidence of functional dissociations among various memory systems. These chapters identify and describe brain systems that mediate emotional memories, modulate memory, or mediate the acquisition of behavioral habits (procedural memory), all concerned with long-term memory abilities, and a system focused on the prefrontal cortex that supports working memory.