Does anyone know anything about 'Jack Chick' publications?

I think people call them 'chick tracts' but I'm not sure. Either way I have been given two, one about Catholicism and one about partying and I was wondering if anyone knew where the information comes from? I'm not condemning or agreeing with what they say I'd just like more information. Obviously some of the information in them comes from the bible but there are other things in there that I'm not entirely sure are right or I haven't heard of before. Also it can't all be based on the bible because the 'partying' one for example is about going out to night clubs. Anyway I was just wondering where the information in them comes from and if the general opinion is that its right.