Archaeologists in the Holy Land like to joke that their profession is vulnerable to a milder form of the syndrome. When scientists find a cracked, oversize skull in the Valley of Elah, it can be hard to resist the thought that it might have belonged to Goliath, or to imagine, while excavating the cellars of a Byzantine church, that the discovery of a few wooden splinters might be part of the cross on which Christ died. This milder malady is nothing new. In the mid-19th century, British explorers who came to Jerusalem with a shovel in one hand and a Bible in the other used the holy book as a sort of treasure map in the search for proof of Christianity's origins.