When Rosemary's Baby hit theaters in 1968, the horror genre as we know it today didn't really exist yet. The scariest flicks of the era were low budget, poorly lit, and corny beyond belief. But Roman Polanski's film helped define a shift towards the same kind of well written, expertly produced and directed psychological horror that had already found a niche on nascent TV. Written by a bohemian novelist, adapted and spearheaded for the big screen by a highly controversial director, and starring a famous actress who was then known only for her work on a soap opera, Rosemary's Baby is a horror film for the ages. But back in 1968, its religious, witchcraftian premise was utterly offensive to mainstream American sensibilities. That, of course, is part of why it's so great.