In this magisterial volume, Iain McGilchrist, a British psychiatrist and writer, reviews recent developments in brain research, particularly the implications of hemisphere asymmetry for individual psychological life and cultural evolution. The book is divided into two parts, the first an in-depth review of recent neuropsychiatric research findings and what they tell us about brain hemisphere functions, the second a discussion of the impact of brain asymmetry on historical trends, specifically the hegemony of left-brain over right-brain functions in Western culture. McGilchrist's principal thesis is that the brain hemispheres are in continual, hopefully creative, tension. However, he argues that over the last several centuries the left brain's attitudes of rationality and control have wrested influence from the right brain's emotionally and relationally based worldview, creating a dangerous imbalance between the mechanized, dehumanized world (now predominant) and the rich, ambiguous world of feelings and relatedness. Despite McGilchrist's friendly attitude