In a clear, nontechnical way, this noted Reformation historian tells the story of how the nascent reforming and confessional movement sparked and led by Martin Luther survived its first battles with religious and political authorities to become institutionalized in its religious practices and teachings. Gritsch then traces the emergence of genuine consensus at the end of the sixteenth century, followed by the age of Lutheran Orthodoxy, the great Pietist reaction, Lutheranisms growing diversification during the Industrial Revolution, its North American expansion, and its increasingly global and ecumenical ventures in the last century.