Claims that this film 'invented' the caper movie may seem excessive, since this wasn't the first time a heist had been depicted from the crooks' point of view. But what made The Asphalt Jungle so fresh was the sympathy and sensitivity with which it characterised its 'crooked' heroes.
One of the studio heads (Louis B. Mayer, I think) famously said he 'wouldn't cross the road to see that Asphalt Pavement thing' because it was about 'ugly people doing ugly things'. In fact, the criminals in John Huston's film are far less 'ugly' than the ones contemporary audiences were used to, and this may in fact have been what Mayer found so discomfiting about the experience.
As Louis Calhern's crooked banker says when trying to soothe his wife's fears about the criminals with whom he associates, 'they're not so different really - after all, crime is only a left-handed form of human endeavour'. The moment sums up the film's outlook, and Huston delights in juxtaposing the single-minded prejudice and condemnation of the 'good citizens' in the film with the essential decentness of his three-dimensional protagonists.
Huston is sometimes credited with making the first 'true' film noir, The Maltese Falcon. With The Asphalt Jungle, he gave the Noir genre more depth and sophistication and sheer human feeling than had even its greatest exponents (Wilder, Tourneur, Huston himself, etc) during the 1940s. And the impression stuck: The Killing and Rififi spring most readily to mind as direct imitations of The Asphalt Jungle.
This is as beautifully photographed, written, acted and directed a crime film as you will ever see, and why there aren't already a hundred gushing reviews for it on this page I really don't know. You need to see it.