The history of untouchability remains a subject yet to be fully explored, scrutinized and reconstructed, and not without tremendous effort. In unraveling the elements of this complex socio-historical fabric, several questions and circumstances are salient. To begin with, what is the origin of the social discrimination that continues to be perpetrated upon certain social groups? What has been the relationship between social dis­crimination and the concept of pollution or sin? These problems have special relevance to the emergence of socially discriminated groups in ancient India like Ca]n]dala. What, then, is the difference between social discrimination in ancient India and untouchability in medieval India? The formative process of untouchability is still clouded in this regard with the darkness or obscurity history. The focal point of this process might be assumed to be the post-Gupta period, but only a more minute investigation will lead to its confirmation. Then again, what is the reality of social dis­crimination against the depressed castes in medieval India? Its historical change and areal diversity poses a perplexing issue. And finally, what were the problems inherent in the transformation of untouchability under British colonial rule and the subsequent development of the liberation movements of the depressed castes which constitute the modern phase of the problem of untouchability? This volume represents the endeavours of Japanese scholars to ad­dress these vital concerns.