A little knowledge is a dangerous thing for Robert De Niro in Brian De Palma's "Hi, Mom!"

Travis Bickle wasn’t the first volatile Vietnam veteran that Robert De Niro portrayed. Years before the blistering violence of Taxi Driver, the great actor twice played Jon Rubin, a Peeping Tom/former soldier trying to make his way in a New York City that had gone to seed. De Niro handled the role in a pair of dark comedies for Brian De Palma: 1968’s Greetings, which was largely forgettable, and 1970’s Hi, Mom!, a raucous if scattershot machine gun of a satire that fired at everything from urban decay to the sexual revolution to guerilla theater to Black Power to white liberals.

Rubin, a demolitions expert in Vietnam, is discharged into a crappy, crime-ridden New York during the start of the city’s slide into economic malaise. After renting a rat trap for forty bucks a month from a disgusting landlord (Charles Durning), the peeper tries to parlay his voyeuristic tendencies into a career as an erotic filmmaker. Rubin talks a blowhard porn producer (Allen Garfield) into giving him two grand so that he can record the sexual exploits of his neighbors using a telescopic lens. When the residents across the way turn out to be bores, the auteur tries to spice things up by seducing his comely neighbor Judy Bishop (Jennifer Salt). But a camera malfunction messes up the big scene, and the veteran decides to turn his attention to an extreme guerrilla theater company that hopes to expose the Caucasian silent majority to Black Power. The film really takes off at this point, not only mocking the excesses of the theater troupe but sort of sympathizing with them.

“You know, tragedy is a funny thing,” Rubin says at one point, and sometimes it is in this intentionally crude movie that matched the madness of its time and place with a craziness all its own.•