David Fincher is one of my favourite directors, if not top of that list, and while he's made some superb films so far in his career, I don't think I've ever enjoyed or admired any of them as much as Zodiac. The case behind this movie has fascinated me for many years as I'm a sucker for a good, unsolved mystery, and Fincher's deconstruction of the case in forensic detail only adds to the fascination. Almost documentarian in approach, Fincher pieces together the Zodiac mystery while at the same time creating compelling drama thanks to a superb ensemble cast.

The span is huge, covering over twenty years in 2 1/2 hours, a running time that feels remarkably sprightly given how Fincher never labours at any point. Thanks to James Vanderbilt's detailed, painstakingly researched screenplay, the whole investigation is on show here, driven by three central players who Fincher anchors the piece around, without ever needing to stop for too long and divert into personal drama. Jake Gyllenhall has never been better than here as Robert Graysmith, the quiet cartoonist for the San Francisco Chronicle who becomes steadily obsessed with discovering who the Zodiac is; he details Graysmith's obsession in compelling fashion, quiet and methodical and entirely believable as a man getting sucked into files, evidence, reports and statements. Equally superb is Mark Ruffalo as Dave Toschi, the dogged California detective who is pushed to breaking point in trying to nail the Zodiac; he drives the middle of the story for a good 30 minutes and keeps the wheels firmly on as a dedicated man, but one who chooses to not let it almost destroy him like Graysmith. And finally it's the incomparable Robert Downey. Jr as Paul Avery, at the beginning a whip smart, charismatic journalist (who Downey. Jr can play in his sleep) who ends up broken and defeated by the Zodiac; the actor plays his descent beautifully, fuelled by drugs & alcohol, no less forgotten when the narrative leaves him behind for the final third.

It's Gyllenhall who pushes to Fincher's open-ended, very honest climax - real life dictates there are no easy answers to the Zodiac mystery, yet Graysmith gets the closure we needed: he knows by the end who it is, even if he can never prove it, and to some extent so do we; that's a big reason Fincher's picture works so well, as what could have seemed a folly ends up giving us answers, even if we'll never know for sure, while equally breaking down the three men at the centre of seeking them - flanked, it must be mentioned, by some excellent supporting turns in particular by Chloe Sevigny who does well in an underwritten role as Graysmith's wife, Anthony Edwards as Toschi's partner and in particular John Carroll Lynch in a creepy turn as the man who may well have been the Zodiac, playing with perfect ambiguity.

It's a marvellous picture, the result of a true auteur at the top of his game. Zodiac has a long reach, could have been a jumbled mess of blank characters delivering exposition, masses of dull statistics and a dry, puzzle based texture. Yet Fincher fills it with atmosphere, evoking the 60's/70's setting richly while filming straight, no tricks or cutting corners, letting the excellent performances and admirable script speak for themselves. His best film so far, in my opinion, and a highly recommended personal favourite.