Even before co-star Heath Ledger was found dead Jan. 22, "The Dark Knight" was being eyed as one of this summer’s most prominent, astonishing tent poles - a lightning rod of a sequel that towered above this month’s parade of routine blockbusters (this weekend’s "The X-Files" etc.).

But ever since the shocking discovery of his body in a New York City apartment, the focus has fallen squarely on his final completed performance. With the film now finally in theaters, words such as "Oscar" and "tour de force" are being bandied about, all this talk about the man and tragedy trumping talk of the character and the film.

It wasn’t always so. Back last autumn, when online fans got their first sneak glimpse of Ledger as the Joker in a number of promotional images, the various entertainment blogs launched into a frenzy, about the way the smiling, creepy face of Jack Nicholson had been replaced by the demented, crazed look of Ledger. This is not a version of the Joker that any of them had ever seen before.

Quickly, word started to spread that it wasn’t just the Joker; "The Dark Knight" was going to take the franchise into places far darker than fans had never seen before.

Ledger’s passion to provoke

For any film lover, it was indeed tragic that Ledger, a man of such talent and promise, died so young. The one and only time I met him was during his press tour for the light-hearted period romance "A Knight’s Tale," a genre experiment that fell far short of brilliance. But what was so remarkable about Ledger was his conviction in saying so himself. Sitting down with the man, he criticized the film freely, and criticized the studio’s marketing campaign, which was presenting the film not as an ensemble comedy but essentially as a Heath Ledger picture.

He was a straight-shooter of a movie star - a fact made even more remarkable that he worked during this era where publicists run the show. Most major actors won’t sit down with a reporter without their press person sitting by their side, moderating questions, but Ledger favored honesty over security. So it sort of makes sense that he would be sought out by a director like Christopher Nolan - the man behind the ingenious "Memento," the stylish "The Prestige" and the awesome "Batman Begins" - to re-invent the character that was made famous by Jack Nicholson.

If he were still around today, to talk about this particular film, he would surely be the first to try and steer the conversation away from his celebrity, pointing people instead toward the work - a film that once again establishes "Batman" as the standard-bearer of the big-screen comic books.

From television to the movie theater, from the ‘60s through the present, "Batman" hasn’t just been one of the most vital comic book brands, but also one of the most influential comics to be adapted for mainstream audiences. And as it’s evolved from the pastels and exclamation points of its television series to the Tim Burton years - filled with black city streets and stunning gadgets - and the Nolan years, rife with the grays of moral and ethical conflict, "Batman’ has asserted its longevity and creativity.

Influence on the movie industry

In the past three years, since "Batman Begins" gave us not only a more psychologically complex Bruce Wayne - played this time by the reserved Christian Bale - but a more dreary and frightful Gotham City, and a more fearsome Batman, the franchise’s influence has once again been on display. In the wake of "Batman Begins," audiences started to witness the darkening of such other franchises as James Bond ("Casino Royale") and Teenage Mutant Ninja Turtles ("TMNT"), and the introduction of such dark new visions as "V For Vendetta" and even this year’s "Iron Man."

This is nothing new. Just consider the various shades of "Batman." During the "Batman" television series in the ‘60s - and in the associated 1966 film - the caped crusader was a man dressed in pastels, joined by wacky sidekicks, engaged in cartoonish violence that always was spun as colorfully absurd. The theme was always the same: Batman, our infallible hero, found new ways to trounce the bad guys and restore order.

Then in 1989, Burton set the stage for a Batman more focused on realistic special effects, and sweeping cityscapes, putting the Joker up in the bell tower, and sending Batman crashing through Gotham in his Batwing. A breakthrough in its day, Burton’s "Batman" went on to inspire "The Batman Returns," the animated "Batman: Mask of the Phantasm," and a similar focus on technology and darker tones can be seen in such other franchise titles of the period as "Dick Tracy," "Star Trek: First Contact" and even "Mission: Impossible."

Starting in 1995, Batman started to sputter, falling victim to the trends affecting all blockbusters of the time - a focus on comedy and talent. That year’s "Batman Forever" focused on fluorescents and comedy, 1997’s "Batman & Robin" was downright silly, and both titles focused on lining up the stars: George Clooney, Val Kilmer, Jim Carrey, Arnold Schwarzenegger etc. But in 2005, "Batman Begins" turned things upside down yet again, putting the focus on the psychology and the back story, rejecting the escapism of the 1966 "Batman," the gadgets of the 1989 "Batman" and the A-list focus of the 1997 "Batman."

With each reincarnation, the same storylines and the same villains have been dusted off (the Joker has been the central enemy in four different films). By all accounts, things should have grown stale by now, but every time, the adventure has found a new way of making the same story fresh and vital for a new generation. More than any other movie franchise based on a comic, "Batman" has proven capable of reinventing itself with the times - and through that reinvention, it has exerted a profound influence on the entertainment industry.

In 2008, we have now witnessed the darkest reinvention of the franchise yet, an adventure that plunges us into the depths of a corrupt city, the heart of a flawed hero, and the tortured soul of a demented killer. And it seems only fitting that Ledger’s final complete performance does more than just add to the "Batman" canon; it broadens the range and depth of the classic superhero villain. Rather than merely going over the top with a caricature, Ledger ends his career by showing all other actors the way that comic book characters can be given depth and dimension.

And there’s every reason to believe, as we wait for the next "Spider-Man," the next "Iron Man" and this autumn’s James Bond sequel, that the impact of both Ledger’s gritty performance and "The Dark Knight" in general will be felt for years to come.