Hee. I think with Bourne it is safe to just skip the books. I've read the first book and it is basically a different story. There are a few similarities such as the amnesiac spy plot and the frantic travelling to discover the truth. And as far as I can make out the plot in film 2 & 3 differ even more from the books. So, just watch the film and enjoy the angst that is Bourne. ;)