AMERICAN GRINDHOUSE

Opens on Friday in Manhattan.

Directed by Elijah Drenner

1 hour 22 minutes; not rated

The documentary “American Grindhouse” is Exploitation 101: a textbook-style history of the seamier side of the movie business. The director, Elijah Drenner, proceeds chronologically from the silent “Traffic in Souls” (1913) and the pivotal “Freaks” (1932) through categories like birth of baby, nudie cuties, roughies, blaxploitation and women in prison, before the exploitation-film business  and his narrative  falls apart in the 1970s with the advent of hard-core pornography and “Jaws.”

In its academic approach, “American Grindhouse” is like sex ed: the lecture gets tedious, but it’s worth sitting through for the pictures. The clips, from unnamed nudist-camp “documentaries” to classics of the genre like “Scum of the Earth” and “Ilsa, She Wolf of the SS,” are consistently diverting and sometimes surprisingly artful. The commentary, from film historians and a large group of middle-aged and older veterans of the business, can be obvious and repetitive. But the directors John Landis, Herschell Gordon Lewis (“Scum of the Earth”) and Don Edmonds (“Ilsa”) provide self-deprecating humor and pungent anecdotes.

After taking his story into the ’70s, Mr. Drenner skips ahead three decades and concludes that the grindhouse spirit is still alive, if only as a subject of parody and homage by contemporary directors like Quentin Tarantino.