It's been a church, a mosque and a synagogue. Jesus is said to have dined there. James, his brother, is believed to have been interred there. King David may be buried beneath the floor. The subject of intense speculation by both scholars and the faithful, the Cenacle on Mount Zion--also known as the Upper Room of the New Testament gospels and as the Tomb of David--has remained a mystery for centuries. Claimed by Jews, Christians and Muslims, the sacred structure continues to evoke passionate controversy. Does it date back to the time of Christ? Was the Last Supper celebrated there? Is this the place where the Holy Spirit descended on the apostles on the first Pentecost following Easter Sunday? Did King David's remains ever lie there? These and many other questions are explored in this first-ever study, offering a readable, fully researched narrative account of the Cenacle's history, archaeology and imagery.