This ground-breaking book has been in print since 1974. Earlier editions of the book were seminal in delineating brain-behavior relationships; the current edition expands this theme using the most recent data from the neurosciences and molecular biology. Earlier editions focused on the behavioral aspects of neurological conditions and the neurological aspects of psychiatric disorders. While this is still the focus of the book it has become clear from many research studies that the environmental events and emotions can alter brain structure , thus finally bringing a scientific basis to psychological events. We have also added a valuable clinical chapter on differentiating the etiologies of disturbed behavior. This comprehensive text by two authors avoids the deluge of facts and duplicationof material often found in multi-authored texts to leave the leader with a consistent approach to understanding and diagnosing disturbances of behavior. While the book is directed towards medical students, residents, psychiatrists and neurologists it has been widely used by many varied health professionals, pyschologists ,and lawyers.