Several years ago Bruce Feiler headed off to the Middle East for a journey that became a bestseller titled Walking the Bible. His new book, Abraham (Morrow), explores three religious traditions which share the ancient patriarch.

Did you set out to write about Abraham as a possible way for Islam, Christianity, and Judaism to connect?

No, not at all. Walking the Bible describes the year that I spent retracing the five books of Moses through the desert, and I was actually working on a follow-up, which would look at the rest of the Hebrew Bible and the New Testament. Then I was in New York and got a call from my brother on the morning of September 11. He said: "Look outside your window."

We began to hear these questions: Who are they? Why did they hit us? Can the religions get along? And one name echoed behind those conversations. One man stood at the heart of these religions that suddenly seemed to be at war. Abraham is the shared ancestor of Judaism, Christianity, and Islam. He stands at the heart of these three faiths. And yet you know almost nothing about him.

The reason that this matters is because if we're going to understand that this ultimately is a family feud, then we have to understand that we have all grown up with our own tradition. And if we want to begin the process of reconciliation, then in some ways we have to do an Abrahamic thing: leave our own tradition and go forth to this destination where God calls us. This is the land where all the families of the earth are blessed by one man.

In your research, what did you learn about the historical Abraham?

There's no archaeological evidence that any of the events in the first five books ever took place. So we don't know that Abraham lived. In some ways that's not surprising, ...