Clinical neuropsychology, i.e. the study of patients with cognitive disorders due to lesions of the central nervous system, has for many years been the leading or, in the case of language, the only source of knowledge about the neural basis of cognitive function. This state of affairs has changed considerably in the last two decades. The "cognitive revolution" has led to extensive developments in the modelling of cognitive functioning in normal subjects; at the same time, modern functional imaging techniques have provided new opportunities for the investigation of normal subjects engaged in cognitive tasks. These recent advances, together with other developments in the field of neurophysiology and experimental psychology, have been instrumental in the definition of a new field of investigation, called "cognitive neuroscience". This increasing body of knowledge must be confronted, and whenever possible integrated, with the teachings of clinical neuropsychology. The aim of this book is to provide an introduction to this "basic science" from the vantage point of the possible applications to the practice of behavioural and cognitive neurology. It attempts to integrate cognitive neuroscience and the clinical practice of behavioural and cognitive neurology. For this reason, the review of the classical syndrome of neuropsychology, such as aphasia, unilateral neglect and dementia, is preceded by a summary of current cognitive models. The first section is thus devoted to selective summaries of current models of cognitive functions and of their neurological correlates; the second discusses diagnostic issues; the third provides an overview of clinical presentations, and attempts an integration with the first section; finally, the fourth section is devoted to treatment and management issues.