It tells the true story of the least successful assassination attempt you’ve never heard of, when furniture salesman Sam Bicke boarded a plane in 1974 with intentions to crash it into the White House.

A teenage girl takes up a specialist military sniper rifle and makes a perfect shot of it with no training, improper handling and in very low visibility. A helicopter flies — nose down — close enough to the ground to clear a path by slicing its attackers into a bloody shower of body parts.

So your best bet if you want something just like the book is to read it. If you want to appreciate the movie for what it is, forget everything about Mathieson’s novel except the premise, because as a piece of cinema, I Am Legend is among the two or three best science fiction movies of 2007.