The astonishing growth of Christianity in the global South over the course of the twentieth century has sparked an equally rapid growth in studies of ''World Christianity,'' which have dismantled the notion that Christianity is a Western religion. What, then, are we to make of the waves of Western missionaries who have, for centuries, been evangelizing in the global South? Were they merely, as many have argued, agents of imperialism out to impose Western values? In An Unpredictable Gospel, Jay Case examines the efforts of American evangelical missionaries in light of this new scholarship. He argues that if they were agents of imperialism, they were poor ones. Western missionaries had a dismal record of converting non-Westerners to Christianity. The ministries that were most successful were those that empowered the local population and adapted to local cultures. In fact, influence often flowed the other way, with missionaries serving as conduits for ideas that shaped American evangelicalism. Case traces these currents and sheds new light on the relationship between Western and non-Western Christianities.