Roger Corman is, was, and will always be the King of that too-often-dismissed, taboo genre. Now 87, the legendary director and producer has been toiling in the drive-in trenches for nearly 60 years. During his career he’s overseen 400 movies–and he’s still cranking them out today. Movies about women in cages, slumber party massacres, and piranhacondas.

Some of those movies were brilliant (his ’60s Edgar Allan Poe adaptations starring Vincent Price, for example); many were bad. Either way, I’d argue–and I do in my new book, “Crab Monsters, Teenage Cavemen, and Candy Stripe Nurses”–that Corman is probably the least-known/most influential figure in Hollywood over the past half century. Not only because of the delicious guilty-pleasure cinematic junk food he cooked up, but also because of the many brilliant careers he helped jumpstart. While Corman may not be a household name, check out this roster of actors and directors who got their first gigs on his low-budget movies: Jack Nicholson, Martin Scorsese, Sylvester Stallone, Francis Ford Coppola, Robert De Niro, James Cameron, Sandra Bullock, the list goes on.

So what exactly is a B-movie? The easy answer is, not an A-movie. Back in the ’40s, when films unspooled as part of a double feature, the A-movie was the star-driven, ritzy, big-budget main attraction. The B-movie was the shorter, cheaper, usually shoddier film tacked on to fill out the two-for-one bill. But hey, who cared? After all, at drive-ins, teenagers were usually too busy necking at that point to care about the second movie’s plot–not that they’d be able to follow it anyhow. But “B” didn’t necessarily stand for Bad. Sometimes these celluloid stepchildren were better–or at least more entertaining–than the self-serious A-picture.

Surprisingly, when double-features started to be phased out, B-movies didn’t die. If anything, they thrived. The ’60s and ’70s became a new golden age for non-studio B-movies (also known as “grindhouse movies” or “exploitation movies”). Their low budgets and the even lower expectations that came with them, allowed them to sneak in the sorts of subversive themes and titillating subject matter that respectable Hollywood was too skittish to touch. They are unpolished gems waiting to be discovered by a new generation. Hence our subjective, dirty-dozen list of the Best B-movies ever made…