The rise of authoritarian Hindu mass movements and political formations in India since the early 1980s raises fundamental questions about the resurgence of chauvinistic ethnic, religious and nationalist movements in the late modern period. This book examines the history and ideologies of Hindu nationalism and "Hindutva" from the end of the last century to the present, and critically evaluates the social and political philosophies and writings of its main thinkers. Hindu nationalism is based on the claim that it is an indigenous product of the primordial and authentic ethnic and religious traditions of India. The book argues instead that these claims are based on relatively recent ideas, frequently related to western influences during the colonial period. These influences include eighteenth and nineteenth century European Romantic and Enlightenment rationalist ideas preoccupied with archaic primordialism, evolution, organicism, vitalism and race. As well as considering the ideological impact of National Socialism and Fascism on Hindu nationalism in the 1930s, the book also looks at how Aryanism continues to be promoted in unexpected forms in contemporary India. Using a wide range of historical and contemporary sources, the author considers the consequences of Hindu nationalist resurgence in the light of contemporary debates about minorities, secular citizenship, ethics and modernity.