I haven't read the books, but someone told me the first 2 followed them very closely >.>
Oh well, since I haven't read the movies were still fricking awesome.
That person either lied, never read the books(or read the books based on the movie like a moron), or they're just a dumbass.
The ONLY real similarities between the books and the movies are that a Jason Bourne lost his memory. The entire point of the books was completely removed from the movies, the plots are completely different. The writer of the screen play was told to
not read the books before he wrote the screen play; so there's no way they're similar.
In the first book, you find out that he's not really an assassin, he's a spy
playing an assassin; and his mission is to lure out and capture/kill Carlos the Jackal. Jason Bourne isn't even his real name, just the name of a dead soldier who was in the same unit as the main character in Vietnam.
In the second book, someone in Asia has revived the Bourne legacy, but instead they're a real assassin, not just someone taking credit for kills to build up a reputation. The original Bourne gets called in to help stop the fake and to protect his wife from those who think he's the one actually killing people.
In the third book, Carlos the Jackal comes back to kill Bourne's family and Bourne has to come back to the life of a spy/assassin to kill Carlos.
Now, those are incredibly basic simplifications of the plots; but they are in no way similar to the plots of the movies. They've written out 3
major characters from the books, although they might have put in a completely different character with a similar name for one of them, like they did Marie. The movie Marie is in no way similar to her counterpart in the books either, and she was never killed.
The Bourne movies are great movies, don't get me wrong, but they are
horrible adaptations of the books.