Though “the bus” is now a catch-all phrase for a cinematic fake-out, originally it referred to an actual bus. In Jacques Tourneur’s 1942 film “Cat People,” a bus roars and hisses to a stop right as the audience thinks the cat person is about to attack, but nothing happens. That kind of fright fakery makes up half of today’s horror flicks, but it was a pioneering necessity for Tourneur and his B-movie producer Val Lewton, who, as we learn in this insightful and compelling documentary, actually volunteered to leave his job as David O. Selznick’s assistant to make low-budget horror pictures for RKO.

When he learned his first script was called “Cat People,” however, Lewton actually offered Tourneur the chance to back out. He didn’t, and the resulting benefit for mostly World War II-era cinema was not just this excellent production from Martin Scorsese, but a string of movies now considered by many to be art classics. Many of them were released on DVD last month as a collection of Lewton productions including “Cat People,” “I Walked With a Zombie” and “The Body Snatcher.”

Scorsese shows that Lewton’s productions aren’t just dusty cinéaste treasures. They were also hits with their original audiences. Perversely, Lewton’s success didn’t translate into more freedom or money. Earning a simple salary for his efforts, Lewton found his creative power ever more stripped with each film, as the heads of RKO simultaneously made things more difficult for their producer. Though a sound explanation is never really offered, the feeling one gets is that once you were found to be good at something in Hollywood in those days, the powers that be lashed you to it with all their might.

No matter how impinged Lewton was by various constraints, Scorsese tells us, he was able to turn in one individual, compelling work of art after another during his B horror years with RKO. Be prepared to spend a lot of time and possibly money on this set, since the introduction is an excellent argument to stick around for the shows. (NR)