THE AMBER ROOM of the Catherine Palace in Tsarskoye Selo, Russia, is the Loch Ness Monster of modern art history. For the past sixty years the occasional drunk or crackpot has come forward to say he or she has seen it, only to be proved befuddled or mischievous.

The Amber Room, or Bernsteinzimmer, was stolen by German troops in 1941, after they invested Leningrad. Its panels dismantled, it was taken as a trophy to Konigsberg Castle, in the Baltic coronation city of the parvenu Prussian monarchy, and disappeared as the Russians laid siege to Konigsberg in the early