He believes the second scroll is still out there and it could be the key to the greatest archaeological prize in history.Interestingly (at least for me), the source for this idea seems to be the Treatise of the Vessels. It is correct that the second scroll mentioned at the end of the Copper Scroll has never been found, but it is not to be confused with the entirely legendary bronze tablet supposedly hidden at the time of the Babylonian Exile according to the Treatise of the Vessels.
"What if finding the treasures of the Copper Scroll did in fact lead to the Ark of the Covenant being found?" he asked.
Rosenberg may be on to something.
Ancient Jewish writings say the ark and other first temple treasures were hidden by priests before the invasion of the Babylonians.
Their locations were inscribed on a tablet of copper.
Rosenberg said, "The Key Scroll has never been found, nobody has any idea where it is."
UPDATE: I see that I have already criticized Rosenberg on this issue here. But his book does sound like fun.
Also, I have more on the Copper Scroll here.