This jargon-free work presents a comprehensive overview of the way mental functions are divided between the left and right sides of the brain. It reviews the historical context from which the field emerged, focusing on behavioural implications, and intergrating new developments in cognitive neuroscience. The authors cover current neuroimaging techniques such as PET, SPECT, EEG and MEG. This edition has been updated to incorporate present thinking within hemispheric asymmetry.