Retired optometrist Robert Thomas handed a pair of books he filched as an 18-year-old GI 64 years ago to the German ambassador in a ceremony at the National Archives this week. Thomas, 83, found the 400-year-old legal volumes stashed among millions of others in a salt mine while inspecting recently captured areas in World War II and kept them as souvenirs. "I've had these books since I was 18 years old," Thomas said. "I'm relieved. I wanted to return them to the original owners, but I had no clue where to start."