For centuries people have been hoarding their personal belongings and leaving, after they have gone, a wealth of splendid treasures and magnificent forgotten riches. Over the years, many have been drawn into the excitement of searching for these hidden treasures that might reveal lost histories of an individual, a family or a whole culture. Many of the rarest and most beautiful objects in museum collections today were once deliberately placed in the ground by their owners and never recovered until found by an archaeologist, metal detectorist or, in some cases, just an ordinary passer-by. This...