The British Academy book prize was won tonight by Stanley Cohen for his "powerful" book, States of Denial: Knowing About Atrocities and Suffering.

Professor Cohen, of the London School of Economics, beat five other shortlisted books to take the £2,500 prize, which aims to celebrate the best of accessible, academically excellent writing within the humanities and social sciences.

Dame Gillian Beer, chairwoman of the judging panel, announced the winner at an awards evening held at the academy in London. She described the book as "a powerful analysis of an extraordinarily important topic". "How is it possible for witnesses - or participants - in atrocities to deny what has, incontrovertibly, occurred? Can one speak of a culture of denial? In exploring these questions Stanley Cohen has carved out a whole new field of enquiry relating sociology, psychology, philosophy, political theory and personal experience," she said.

States of Denial is the first comprehensive study of both the personal and political ways in which uncomfortable realities are avoided and evaded. It ranges from clinical studies of depression, to media images of suffering, to explanations of the "passive bystander" and "compassion fatigue". The book shows how organised atrocities - the Holocaust and other genocides, torture, and political massacres - are denied by perpetrators and by those who stand by and do nothing.

Professor Cohen is Martin White professor of sociology at the LSE. He received the American Society of Criminology International Division Award for outstanding publication of 2000/2001, the Sellin-Glueck Award of the American Society of Criminology (1985) and is on the Board of the International Council on Human Rights.

The other shortlisted titles were: · Culture and Equality: an egalitarian critique of multiculturalism, by Brian Barry (Polity Press)

· Voices of Morebath: Reformation and rebellion in an English Village, by Eamon Duffy (Yale University Press)

· Radical Enlightenment: philosophy and the making of modernity 1650-1750, by Jonathan Israel (Oxford University Press)

· Origins of the European Economy: communications and commerce AD 300-900, by Michael McCormick (Cambridge University Press)

· Intellectual life of the British Working Classes, by Jonathan Rose (Yale University Press)

The judges for the book prize were Dame Gillian Beer - Chair (recently retired King Edward VII professor of English literature, University of Cambridge); Dr Noel Malcolm (historian); Michèle Roberts (author and professor of creative writing, University of East Anglia); Professor Steven Rose (director, brain and behaviour research group, The Open University) and Dame Marilyn Strathern (professor of social anthropology, Cambridge).