How did a radical, minority movement of dissenters transform into a global religious force that fundamentally reshaped Western civilization? Alec Ryrie, a professor of the history of Christianity, utilizes extensive archival research and primary source analysis to trace the evolution of Protestantism from its sixteenth-century origins to the present day. He argues that the movement's inherent volatility and internal contradictions were not weaknesses, but rather the primary drivers of its adaptability and enduring influence across diverse cultures.

This work is regarded as a rigorous and balanced examination of a complex religious tradition, praised for its ability to synthesize vast historical data into a coherent narrative. The text is suitable for both academic study and the informed general reader seeking a nuanced understanding of Protestantism's historical trajectory.