We have been enjoying reading "The Monuments Men," by Robert M. Edsel. We did see the movie a few years ago, but it was on a plane and I think I slept through most of it.
I read his later works, "Saving Italy" and "Rescuing DaVinci" before our 2017 Village Italy tour, and enjoyed them, especially "Saving Italy."
"Monuments Men" covers a lot more ground than either of the other two, and probably covers way more than you ever new about Nazi art theft and the work of the Allies to recover as much of that art as possible. It's a compelling read, concentrating on the individuals involved. Getting to know these people personally, - their lives, loves, backgrounds, and children - makes the book more compelling. It's worth the few evenings it will take to read it.
And as a related plug, "Saving Italy" is even better. Edsel found when he was planning "Monuments Men" that he had too much information for a general interest book, so he left out almost all of his Italy information (except about Monte Cassino,) and put it in its own book. Again, more that you ever knew about Naziism, finding and saving art, and the people involved - on both sides.