Many writers, be it fiction or non-fiction, stick to that which interests them and are able to produce an amazing number of essays, reports, theories, books and even novels based upon that which they have seen, studied or experienced.
The late Michael Crighton (who wrote Jurassic Park, Andromeda Strain, Congo, Sphere and created the TV show ER) was well versed in the ideas and theories of science (apparently of the biological, medical and intergalactic kind). Gary Larson, the famous cartoonist behind The Far Side, often depicted animals in interesting situations because he studied biology in college (and is said to have worked for Jane Goodall after he retired from comics). Going beyond printed work, Donkey Kong and Mario creator Shigeru Miyamoto has made a ton of successful games by tapping into the experiences he derived from everyday situations; the levels from early Zelda games were inspired by exploring the Japanese wildlife when he was a child and Wii Fit was conceived when decided that standing on his bathroom scale wasn't interactive enough. And Kate Beaton has created an incredibly successful webcomic based almost entirely on interesting twists on historical events.
Knowledge in any specific subject--be it history, science, outer space or even video games--can make for fascinating pieces of work when presented in a way that engages people.
This worries me.
Not so much the idea of writing what you know. That, like I said, is the freakin' rule of thumb.
No, what really worries me is that I don't really write about that which I know. In fact, I must confess that I'm not very well versed in any one subject outside of game development. And even that was a bit rocky for me; I didn't know what I wanted to do in game development when I signed up for the degree. I just know I wanted to be involved in it. I wore a lot of hats in college and, admittedly, it probably made my life a bit more difficult because I don't feel I've really mastered one particular aspect of the field (that and the fact that I probably spent too much of my time helping others learn software instead of having fun and/or sleeping >_>).
It sort of puts me off that I don't really have anything that I can easily transcribe into my comics short of some joke other than giving myself a seizure because I shifted some 1's and 0's in the wrong direction while working on a color transform in Flash...
For now, I seem to somehow get by with what I picture as interesting situations without any kind of knowledge to back it up. Like a seventeen year old girl forced to look over a country that I still have yet to create a definite culture for. Or cute zombies who play out their family issues by decapitating one another. Neither of which I'm sure I have the proper credentials to write about. Especially when it comes to the zombies.
But somehow, I'm enjoying myself. Not sure why I am. Especially when I feel I don't have enough smarts to add legitimacy to any it.
Strange, ain't it?