The Korean small plates called banchan (which literally translates to "side dishes,") are served ahead of the main course, but they're not appetizers. They represent a category unto themselves: snacks-within-a-meal that function as complements, contrasts, and condiments all at once. And they're totally necessary.
Given that they're not typically listed on the menu and there are 250 million (we counted!) kinds of banchan you may encounter in any given restaurant on any given day, it's not likely a newbie would have any clue what's in all of those little dishes. (Unless it's kimchee -- zero excuses there.)
So here's all the banchan that you're most likely to find in restaurants stateside. Use this in conjunction with our dos and don'ts of Korean dining and our KBBQ guide, and... well, you'll still have a lot of learning to do. This is a cuisine with a lot of moving parts. But at least you'll have a head start.