In a world of disposable summer megahits that make a billion dollars in a single weekend only to be promptly forgotten by the time the next weekend rolls around (hi, Transformers II: Revenge Of The Fallen: The Fallen Rise Again: I’ve Fallen And I Can’t Get Back Up), it’s such a flat-out pleasure to watch a Michael Mann movie. He’s an anomaly in almost every way: an auteur who traffics in $100 million summer tentpoles, a maker of “guy movies” who loves casting interesting and underemployed actresses, a cerebral strategist who choreographs the greatest action sequences in modern film.

Mann’s detached, low-key style may leave some cold, but his latest, Public Enemies, is a feast for his fans. He approaches the story of John Dillinger much the way he did with his other masterful biopic, 2001′s Ali: by examining a pivotal period in his subject’s life instead of going through the motions of a traditional cradle-to-grave narrative. We learn more about Dillinger (an enigmatic Johnny Depp) in the thrilling opening jailbreak than we’d learn in an hour of clichéd childhood flashbacks. He’s an outlaw, but he’s not unreasonable, and his wrath is restricted to hotheaded members of his crew. He’s a professional first and foremost, sort of a Depression-era version of Robert DeNiro’s Neil McCauley from Heat. We learn a little about his background later, though none of that matters to Dillinger. As he tells a pretty coat check girl he’s trying to pick up (Oscar-winner Marion Cotillard), “It ain’t where you’re from, it’s where you’re going.”

Most of today’s great directors don’t have an instantly identifiable style like Kubrick, Bergman or Hitchcock did. Not so with Mann; most anyone could probably watch five minutes of 1986′s Manhunter and 2004′s Collateral and tell you the same guy made both. Mann’s films have always been visually interesting, working exclusively with celebrated cinematographers Dante Spinotti (L.A. Confidential) and Dion Beebe (Memoirs of a Geisha) to achieve the minimalist widescreen canvases that have become his trademark. The adoption of digital video in the early Aughties invested his films with a level of hyper-realism that makes them feel even more vital and kinetic. This is his first film, though, that applies that improvisatory DV aesthetic to a period piece, and the results are striking.

Some have complained that Public Enemies doesn’t go deep enough in exploring its sociopath Robin Hood of a protagonist. These people are missing the point. This is a revisionist gangster movie that demythologizes a character and an era that, for most of us, exist only in legends. We see the daring bank robberies, but we also see a man at the end of his rope whose friends are all dead or in jail and whose only remaining human connection sells him out to the feds. We see the nice suits and cool cars, but we see them ripped apart by bullets and demolished in high speed chases. Depp’s Dillinger is quiet but he isn’t passive, standing in stark contrast to flashier creeps like the psychopathic Baby Face Nelson (played here by the great Stephen Graham, who made a big splash in This Is England a few years ago).

There’s a lot to discuss here, really enough to fill a book. I haven’t even mentioned the timely look at the changing technology and ethical lapses on both sides of the law as a predatory J. Edgar Hoover (a scene-stealing Billy Crudup) fights for his political life as Dillinger evades him, or the class struggle that made a bank robber into a man of the people stealing from the banks who stole from them, or the art-imitates-life strangeness of Dillinger’s eerily cinematic final moments as he’s killed outside a movie theater showing a Clark Gable movie obviously inspired by his own story. Public Enemies is full of great ideas, brought to life by a man who’s unquestionably on a shortlist of the best filmmakers working today.