The opening scenes of Ray Greene's documentary Schlock!: The Secret History Of American Movies demonstrate how easy it is for a celebration of pop trash to labor under contradictions. For the most part, Schlock! is a well-researched and astutely analyzed study of sub-Hollywood exploitation cinema, but early on, Greene coasts on kitsch, laying down condescending clichés about the conservative tenor of the Atomic Age while cutting to unintentionally funny clips from old drive-in staples. Like a live-action version of a Something Weird commentary track, Schlock! asks the audience to take its subject seriously and laugh it off at the same time. Greene does better when he un-arches his eyebrows and delves into the specifics of exploitation history. He covers the impact of traveling carnivals, with their adults-only screenings of "clap operas" and nudist-camp exposes. He reveals the role of American International Pictures in establishing a direct connection to teenage fans without the standard Hollywood machinery, and he lays out how rival drive-in producers used that underground apparatus to reach an ever-more-discriminating audience, making like Hustler to AIP's Playboy. Mostly, Greene discusses how the exploiters' working habits–pre-selling films before any footage was shot, making a movie too quickly to think about what was in it–enabled them to record truths about their times that more respectable movies didn't. Schlock! doesn't say enough about the slow decline of low-budget grime in the wake of blockbuster genre pictures like Star Wars, but Greene interviews most of the key people and adds his own lively observations on, for example, the connection between fumetti and "nudie cutie" movies, between the Kennedy assassination and gore flicks, and between Doris Wishman's use of nudity in the films she directed and her belief in true love. Besides a dualistic approach to its subject matter, what Schlock! has in common with other surveys of pulp ephemera is a belief that the homemade charm of cheap moviemaking is preferable to the dull craftsmanship of the mainstream. That's at least one of the angles of Stephen Parr's historical erotica compendium The Subject Is Sex (available on DVD exclusively at othercinemadvd.com), which also seeks to evaluate the real meaning of prurience. Though the vintage shorts and trailers that make up The Subject Is Sex can be watched on their own, the presentation has been arranged purposefully, starting with the '50s-era documentary Nudism: A Way Of Life?, which sets the tone by encouraging viewers to take a long look at naked bodies and decide if it's possible to do so objectively, without getting aroused. Parr immediately follows the short with a sexy '60s TV cologne commercial, then a trailer for the arty 1972 porn film Dynamite. Over the next hour and a half, The Subject Is Sex pokes at historical conceptions of sexuality and gender, via salvaged footage like a celebrity-filled trailer for the scandal-porn anthology Hollywood Blue, a PSA for the President's Physical Fitness test in which a bare-chested teenage boy gets all sweaty, a military training film on how to give an enema, and a transsexual phone-sex ad. The compilation might have more impact if its segments were trimmed and fragmented more (as Parr does for one of the DVD's featurettes, which quickly runs through some of the other buried treasures he's found), but The Subject Is Sex is still a fascinating show, avoiding the "mockery vs. reverence" trap by letting the films comment on themselves. (To order The Subject Is Sex directly, visit www.othercinemadvd.com.)