Jim Hoft is asking the right question -- why is it that a British paper is the main outlet paying attention to this?
The Daily Mail called it a "flying missile" and looked at the security implications:
It is expected that there will be fallout from the security breach as the Secret Service investigates how close the President came to danger.
The rally was clearly an eventful one - other images showed a naked man being led away in handcuffs by police.
It is not clear if the man was involved in the book-throwing incident - or why he was not wearing any clothes.
Hoft posted a video on Gateway Pundit. Pay attention at the :23 mark:
CBS News has this version of the video -- with some slo-mo and highlighting: