The recent massacre of Christians in Afirca—on the points of machetes—should alert us that more is going on Africa than meets the eye. Much of Africa has converted from its aboriginal religions to either Christianity or Islam. While Islam was ascendant in earlier decades (and centuries), Christianity has caught up.

Christianity, which a century ago was overwhelmingly the religion of Europe and the Americas, has undertaken a historic advance into Africa and Asia. In 1900, Africa had just 10 million Christians, representing around 10 percent of the continental population. By 2000, that figure had swollen to over 360 [...]