<P>This book explores the prejudice against slave descendants in highland Madagascar and its persistence more than a century after the official abolition of slavery. </P><P>¿Unclean people¿ is a widespread expression in the southern highlands of Madagascar, and refers to people of alleged slave descent who are discriminated against on a daily basis and in a variety of ways. Denis Regnier shows that prejudice is rooted in a strong case of psychological essentialism: free descendants think that ¿slaves¿ have a ¿dirty¿ essence that is impossible to cleanse. Regnier¿s field experiments question the widely accepted idea that the social stigma against slavery is a legacy of pre-colonial society. He argues, to the contrary, that the essentialist construal of ¿slaves¿ is the outcome of the historical process triggered by the colonial abolition of slavery: whereas in pre-abolition times slaves could be cleansed through ritual means, the abolition of slavery meant that slaves were transformed on