The third installment of the Bourne series, "The Bourne Ultimatum" is out, and has been raking in the cash at the box office. It has also been getting amazingly good reviews, something I find a bit unusual since dozens of action films with lots of action and little plot have been released before, and not gotten half of the acclaim that "The Bourne Ultimatum" has received.

Not that "the Bourne Ultimatum" is bad - it is not; it is fun to watch, and very well acted. The action sequences are brilliantly staged with long takes and hand-held cameras that practically make the audience a participant in the story. But the story contains some elements that viewers may find baffling.

The film plunges you into the action right at the beginning, as amnesia victim Jason Bourne (Matt Damon) remembers disconnected elements of his past in jump-cut flashbacks. Again, he is being chased, and again he is trying to find out the complete truth about his past - something that may confuse the audience who saw the first two Bourne films and assumed that he had already found out all he needed to. The CIA is also trying to find him again, and once more, they consider him dangerous. CIA operative Noah Vosen (David Strathairn) is especially anxious to "take him down", possibly for shady reasons, and the conscientious CIA Deputy Director, Pamela Bundy (Joan Allen making a return appearance from "The Bourne Supremacy"), who is Vosen's superior, is willing to trust Bourne, but not quite sure if she should.

The action in this film is almost literally non-stop, so much so, that when a quiet moment comes and two characters engage in a normal conversation, one feels relieved. I have seldom seen this much action even in a spy thriller, but it is not mindless action; the audience is also kept wondering what happened to Bourne that he hasn't found out yet.

Another element that spurs him on is the desire to find out exactly why his girlfriend from the previous two films (Franka Potente) was murdered, and to avenge her death.

As I mentioned before, the acting is quite good, with David Strathairn doing a complete transformation from his Oscar-nominated Edward R. Murrow in "Good Night and Good Luck", pitted against Joan Allen's believable and sympathetic portrayal of a law wnforcement official who discovers that someone she has known and trusted has no regard for rules or the limits of his authority.

Other actors turn up as well - Julia Stiles returns as Nicky Parsons, another worker who apparently has some kind of a history with Bourne and tries to help him. Before long, she becomes a potential target of an assassin as well, and there is a hint that if the couple were not so busy trying to escape being killed, they just might become romantically involved. Albert Finney and Scott Glenn also contribute effective cameos as higher-ups who know much more about Bourne's past than they are willing to reveal.

This film will not win any Oscars, but it is an entertaining way to spend a couple of hours, though it is certainly not, as some critics have claimed, the best thriller in years. One suspects that perhaps the critics were awed by director Paul Greengrass's newfound importance. Although he directed "The Bourne Supremacy" (to less acclaim than this latest film, by the way), Greengrass became an Oscar nominee earlier this year after having made the true-life docudrama "United 93", about the ill-fated flight that crashed in Pennsylvania on September 11, 2001.