What do I need to know in order to get into Dexter?

I had the same problem but I love it now. Read a few of the episodes here it`ll help.

http://en.wikipedia.org/wiki/Dexter_(TV_series)

Yes , It's a great show

To get some insight it helps to watch the very first episode

Warning...SPOILERS

It tells about how when he was a kid he liked to kill small animals like dogs etc.

His dad who is a Cop tells him if he can't control his urges , it's best if he channel them , in other words , kill the people who deserve killing , pedophjiles , rapists etc.

So Dexter does this all the while working as a blood splatter expert with the police department

well...in case you dont know its about a man who solves crimes but usually ends up killing the victimizer. he basically gets revenge for the victim because of what the villain did. there arent any things specific that i can remember except for he had a really messed up childhood. if you have ShoTime you could probably watch the earlier episodes. I started watching it on ShoTime when it first premired. Yes, its a show worth watching.