By now it's clear that I'm a big fan of the Harry Potter series, the type who can look past the turgid faithfulness of the first two films and love and be amazed by them, despite their faults. To provide a brief recap of my previous reviews: Chris Columbus's first two films were of that sort of slightly edgy, altogether enchanting storytelling style that makes my inner child soar.

Alfonso Cuaron takes over here with this adaptation of what is generally regarded as the best book of the series; much was made about the director of Y Tu Mama Tambien directing a childrens' film, but most people seem to have forgotten his first American film was a lovely adaptation of Frances Hodgson Burnett's A Little Princess, which, like the Harry Potter films, avoided any sort of sugary pandering to its audience. The series is in good hands -- or better, since even Cuaron's unsuccessful Great Expectations adaptation displayed more visual flair and artistic sensibility than Columbus ever has in any of his films (or even, not counting his Potter films, all of them of them combined).

Here, Cuaron casts Harry Potter and his friends' third year at Hogwarts in a decidedly different light; everything's the same, technically, and yet not. Hogwarts Castle is lit in a harsher light, its great halls no longer emanating warmth and cheerful intrigue, its plazas and promenades dank and showing some signs of decay. It looks like a real castle, in other words. Along those same lines, Albus Dumbledore is portrayed now by Michael Gambon, stepping in for the late Richard Harris; Gambon maintains the twinkle in his eye that Harris so eloquently displayed, but also gives the character a sense of purpose that its previous, humourously aloof incarnation rarely seemed to have.

The whole film is marked with menace, personified most obviously in the presence of the Dementors, the wraithlike guards of Azkaban prison who are sent to guard Hogwarts. Their description in the books were very similar to the Ringwraiths in the Lord Of The Rings series, and so it must have been something of a challenge to come up with an original design. The result is perfect, and rather terrifying; they're more akin to shrouded corpses than spirits, and their presence elicits immediate fear. As they should.

I suppose one could criticize the standard sense of progression that equates 'darker' and 'edgier' with 'better.' I'd counter that, in films like this one, its simply that the approach is a more realistic one, and that the darkness is not an attempt to be hip but something that inherently fits a story that grows with its characters. Ron, Hermione, and Harry are in their early adolescence now; fittingly, they've more to deal with (including the burgeoning, inevitable relationship between Ron and Hermione, which appears in this installment in the form of mutual distaste).

Daniel Radcliffe, Rupert Grint and Emma Watson return to their roles, of course, as do the young actors playing Neville Longbottom, Ron's twin brothers Fred and George, and the other students who've appeared in the other films. I once doubted whether the same cast would be able to last through the entire series; now I think that not only is it possible, but it would be a shame for any recasting to be done. These actors are so integral to the film's success, and there's such pleasure to be found in seeing them progress and grow up with the characters, that I'd be afraid to see anyone else in the parts. As Cuaron recently noted in an interview, it would be far better to simply have the actors play characters slightly younger than they are; and at the rate these films are being produced (the fourth recently began shooting), there shouldn't be too much of a discrepancy.

Save for Dumbledore, all the old teachers return as well; even Warwick Davis as Professor Flitwick is present, although he's had a rather striking makeover. Continuing the trend of there being a new Defense Against The Dark Arts teacher every year (the position seems fraught with malevolent intentions and/or bad luck), David Thewlis makes a great impression as Professor Lupin, with whom the increasingly troubled Harry finds much needed counsel. Emma Thompson, not to be outdone by former beau Kenneth Brannagh, provides some comic relief and one surprising scare as the loopy Professor Trelawney, and of course Gary Oldman is the most touted addition, although his Sirius Black, the titular prisoner, doesn't appear until the climax. Those who haven't read the books may think that Gary Oldman playing a psycho is sort of predictable, but there's a bit more to Sirius than that, and after some initial hystrionics, Oldman gets to have the rare opportunity to show off his more subtle talents.

Timothy Spall and Julie Christie make brief appearances as well. One might have some fun on the IMDB looking for distinguished British actors and guessing which ones will appear in future installments. You can cross Brendon Gleeson off the list, as he's already onboard The Goblet Of Fire, but Tim Roth, Colin Firth and Peter Mullan haven't been tapped yet.

In the two years since I read the book, I'd forgotten many of the details of this story, and thus was consistently surprised. For the most part, I wasn't able to identify that material which Cuaron and screenwriter Steven Kloves have jettisoned or added; regardless, it all flows fluidly, without lull or cessation. The film is twenty minutes shorter than its predecessors (largely due to the scant presence of Quidditch tournaments), and is certainly more breathless and less stately; and the climax is something of a marvel, in that it occurs twice, and that the repetition is not tedious but remarkably complimentary and emotionally moving.

Aesthetically, Cuaron's additions are not relegated to making everything more brooding and unsettling; his frames are full of mist that seem to suggest that magic is literally in the air, and there are details everywhere that will inspire laughter or amazement or both at once. He's populated this magical world with far more interesting people of various ethnicities, and added little stylistic touches, like the way the Whomping Willow is used to signify the changes in season or the old fashioned iris effect that opens and closes scenes, that display a very appropriate sense of visual whimsy. And then there's Buckbeak, the hippogryph, which is a cross between a horse and a bird. It's a computer generated creature, of course, but it's one of very few in the film, and Cuaron must have made sure that extra care was taken with its creation, so that it comes across not as a magical creature but as a real, palpable animal, with real personality. The scene where Harry tames it and then soars on its back through the skies is one of the most joyful and exhilerating special effects sequences I've ever seen; the scene where it meets its unfortuante fate is horrifying, even though we technically don't see anything.

Had Christopher Columbus continued making these films himself, I think I would have been happy with them, if eventually rather indifferent. Shaking things up, so to speak, is a perfect approach, and Cuaron has done such an excellent job at elevating the series that I almost want to see him take another shot at it; but next up, tackling the most unwieldly of JK Rowling's books so far, we have Mike Newell, a competent director who somewhat fails to excite me. For future installments, I'd perhaps like to see Gabriele Salvatores, who recently directed the outstanding I'm Not Scared, or PJ Hogan, whose Peter Pan ranks with the Potter films as one of the best family films in recent years, be given a shot. I suppose, though, that as long as the level of quality achieved thus far is maintained -- a level that has been consistently elevated by each successive installment, exponentially so in this case -- I'll be happy. And if I'm happy, then the rest of the fans will be happy too, since I certainly rank amongst them.