Originally Posted by MeiLin
If you're a Mac user, I cannot recommend Scrivener enough. There is a trial version, but the software itself isn't too expensive. It's the best money I ever spent, myself. http://www.literatureandlatte.com/
Hear, hear. It's so good it would be worth buying a Mac just to be able to use it.
But if you don't want that, and/or don't want a Mac, get LibreOffice (the entirely free, non-Oracle offshoot of Open Office) from documentfoundation.org and use the Master Document functionality. I wrote my first novel that way, and then discovered Scrivener, where I'm working on my second.