President Trump may need a history tutor.

A Very Stable Genius, a new book by Washington Post reporters Philip Rucker and Carol Leonnig based on hundreds of interviews, alleges Trump seemed to know next to nothing about the events of Dec. 7, 1941 when he visited Pearl Harbor in Hawaii for a private tour of the U.S.S. Arizona Memorial alongside his former White House Chief of Staff John Kelly, a retired Marine Corps general.

"Hey, John, what's this all about?" Trump reportedly asked Kelly. "What's this a tour of?"

The authors wrote, per an excerpt in the Post, that Trump did seem to understand Pearl Harbor was significant, but was light on the details. He reportedly appeared to think he was visiting the site of a historic battle, which isn't necessarily an inaccurate description — the attack on Pearl Harbor was a surprise Japanese military strike against a U.S. naval base that prompted Washington's entry into World War II.

Either way, it's generally considered one of the more significant singular events in U.S. history, so it's probably worthwhile for the commander-in-chief of the armed forces to become familiar. Read more at The Washington Post.