People have always lived with the scourge of plague. In the ancient world, epidemics were a frequent catastrophe that the natural world had to offer, along with storms, floods, fires, earthquakes, and droughts. In ancient Egypt, in the time of Moses, disease was one of many such "plagues" visited on the land of Egypt. In the common understanding of the time, these plagues could mean only one thing: the wrath of God.

Humans will always seek an explanation for the mysterious workings of the natural world. For the people of the Bible, plagues were explained as a divine punishment. In modern times, those who might dismiss religious belief offer a different explanation for events described in the Bible. According to some theories, the eruption of a volcano on the island of Thira (Santorini) in the Greek Aegean Sea caused a huge...