The Nazis during World War 2 seized many of Europe’s art treasures. The Rape of Europa in book and DVD form here is about this.
The other 2 books are about the efforts to prevent the Mona Lisa from being seized and on the efforts towards the end of WW2 to recover the art treasures in Italy.
Readers interested should also read the book The Monuments Men which was also made into an excellent movie.
Name the leader from the US or UK that was instrumental in the recovery efforts to which mankind is forever grateful.