Gialli is very much the mother of slashers, and without a lot of these films, it wouldn't exist. Mario Bava is perhaps the one to thank the most; his films like The Girl Who Knew Too Much and Blood and Black Lace are essentials of the genre. Dario Argento is another who pumped out some goodies. All in all, it's a very fun and smart genre, so I'll do my best to see the ones I've yet to.