Paul's apparently overnight change from ruthlessly persecuting Christianity to rigorously promoting it is almost certainly the most significant conversion in history: more significant than Augustine's, and even Constantine's. Without Paul's conversion, Christianity as we know it may well have never even happened. But what actually happened?

The New Testament describes Paul's experience on several occasions: but can the accounts be trusted? Are they even consistent with each other? If we want to understand such a world-shattering experience, do we need to invoke the supernatural? Are there other plausible explanations? And is it right to call the event a "conversion" in the sense that Paul turned from one religion (Judaism) to another (Christianity)? These are all key issues for understanding a pivotal point in early Christian history, one that eventually would have enormous ramifications for the history of the west.