Ancient books in a monastery ... a code left by Nazi soldiers ... a deep fjord ... and a mysterious stainless steel cylinder-all lead to a fantastic war-time discovery.

The one hundred thousand ancient books in the Great Library of the Benedictine monastery were just part of the majestic beauty of Austria's 12th century Melk Abbey. But that beauty was marred when the monks discovered that scores of valuable books had been marked and disfigured by persons unknown.

Wilhelm Gerhard was retained to find the cause. With help from his friend Wolf and 100 monks in black habits, they examined...