What are the different research fields in computer science?

The most concise list I've seen is given in Wikipedia's http://en.wikipedia.org/wiki/List_of_academic_disciplines_and_sub-disciplines#Computer_sciences.  That's pretty close to comprehensive, and certainly not missing anything major.

Computer Science includes a lot of aspects. Well, I think which subject you choose depends mainly on your interests. Even within a same subject, different people do totally different things, e.g. in AI (artificial intelligence) research, some are good at programing while others lie in the study of the mathematical basis. But whatever subject you choose in CS, working hard on mathematics and programming will be always of great help.

It absolutely depends on your interest. You should start to know something from determine what area of: http://en.wikipedia.org/wiki/Computer_science#Areas_of_computer_science your want to study. And yes, all of them required good skills (sometimes even excellent) in mathematics and programming. The less requirements you can find from Information Technology direction (like IT management) and be ready for a long search, because they are not so many. Also if you familiar with medicine, you also can find a lot of research in border between medicine an computer science (including bioengineering) If you close to another directions you can join as an expert of some areas for AI researches, and this is a good explanation about AI: http://artint.info/html/ArtInt_8.html The most important things is area, which determine your direction and level of your programming and mathematics skill

First, some of these answers state that you must be good at programming and math. This is not true. I don’t think anyone has ever said that either is a bad or worthless skill, but many people in some areas do little programming or math, but I have to qualify this. Like any academic field, CS has its purists, but for most researchers it’s necessarily a very interdisciplinary field, so people without programming skills or advanced math skills can find places to contribute. In addition, programs like those in information science (which is not even remotely the same as information systems) often offer graduate education and research opportunities that don’t require programming or math.Two critical areas, human-computer interaction (HCI) and artificial intelligence (AI) are heavily, heavily dependent on psychology; the focus is mostly on experimental or computational cognitive psychology, but social psych is playing growing role. Many people who’ve studied psychology have anywhere from decent to amazing skills with applied stat (especially those in experimental psych). In addition, HCI has been a welcoming area for people in art and design. One of my absolute favorite people in the field, https://www.hcii.cmu.edu/people/jodi-forlizzi, is a full professor in the Human Computer Interaction Institute in the School of Computer Science at Carnegie Mellon University, which is an agreed-on top-five CS program and considered by many to be the top CS research institution in the world. She had a BFA and an MDes and no degree in CS when she started, although she eventually completed a PhD in CS at CMU. She’s not the only person to go from art to CS.Second, if you don’t have a degree in CS, you probably have done little or no programming, and if you don’t have a degree in STEM, you probably have little or no college-level math, and you may fear these are things you’ll be naturally bad at. However, we have no solid predictors beyond interest. I’m not going to claim that anyone who finds it interesting can master programming, but I will say that I’ve seen student succeed more on grit and determination than anything else, and I’ve seen students with natural gifts for programming fail because they weren’t willing to apply themselves. The notion that you need great math skills is nonsense; we don’t cover much math beyond high-school-freshman algebra in the first year (there are those who use math for examples, but if your prof forces you to solve trig problems in intro CS1, that’s because they like trig, not because it’s required). Most BA CS programs only require two semesters of math (Calc I and Discrete Math).I didn’t take college-level math beyond on semester of calc (which I did poorly in and remembered nothing from) and I didn’t take CS1 (the introductory computer science/computer programming course) until my senior year, when I needed it for a gen ed. I adapted quickly because I like problem-solving and because I have a decent facility with language, sharpened by several years of demanding writing assignments and good (but sometimes harsh and not always nice) critique from faculty in my chosen majors (history and English).I eventually learned a great deal of math because there are lots of applications for math in CS, unlike in math, where “applied” is considered a pejorative by many. However, I only recently accepted that I can’t really describe myself as “not good at math” anymore. Like most (literally most) people, I felt my math skills were far below-par.There are basically two kinds of CS: first, studying computers and computation, how they work, and how to make them work better, and second, how to make computers do interesting things. I’m in the latter camp, and frankly, there are more of us, research in our areas gets more funding, and most of us consider the notion that we’re ideologically impure to be pretty laughable.If you want to study CS, I recommend taking some CS courses: CS1, CS2 (usually object-oriented programming, but not always), data structures, algorithms; depending on the school, this is typically three or four semesters, and they have to be taken in sequence. Also take some math: calc I, discrete, and an intro prob/stat course. However, I did not follow this recommendation at all, and you don’t have to; it’s just the most straightforward way. If you find yourself able to do these and to do reasonably well in the CS courses, and you enjoy yourself, continue study or get a job. You can usually get a programming job (maybe not the world’s greatest programming job) with just this (or even less; although I would recommend self-studying web and database development), or you can go into an MS program (at least theoretically). Work is great because you get paid, you learn more, and you get valuable experience.If you find you can’t succeed in programming or you hate it (but really give it a try! it’s not easy) but still want to be in CS, then the two most practical paths are cognitive psych and art.I know a guy in data science who is entirely self-taught and knows more than any of my undergrads about most areas (I’m sure he has holes, but nothing of critical importance, and we all have holes in our knowledge). He does have a PhD; it’s in classics (Latin and Greek).There’s no one way to do CS. I found that computers allowed me to earn a pretty good income while being creative, and they allowed me to explore concepts of mind and thought that are limitless. Others are entranced by other things. Find your passion.Good luck!