Gangs of New York

''Gangs of New York'' is an important film as well as an entertaining one. With this project, Mr. Scorsese has made his passionate ethnographic sensibility the vehicle of an especially grand ambition. He wants not only to reconstruct the details of life in a distant era but to construct, from the ground up, a narrative of historical change, to explain how we -- New Yorkers, Americans, modern folk who disdain hand-to-hand bloodletting and overt displays of corruption -- got from there to here, how the ancient laws gave way to modern ones.