So why is it called an advance? Because technically, the writer gets a percentage of the cover price of the book -- usually 10%, though that can vary slightly depending on many things. But 10% is pretty standard. That percentage is called the royalty. The advance is an advance payment on royalties. Rather than getting paid as copies are sold, you get the advance up front. Then, when and if sales of the book rise above ten times the advance, you start getting royalty checks for 10% of the cover price of each new copy. This is accounted and paid quarterly or semi-annually, depending on the publisher. A lot of things can affect these numbers, but this is the basic outline. A lot of small presses, by the way, pay only royalties, no advance. This is a perfectly legitimate way to do business, and happens because small presses don't have the cash reserves of larger publishers and can't lay out the money before it starts to come in. In theory it should amount to the same thing: whatever you were going to make, you'll still make, because you'll get your percentage as the book sells. In fact, it's riskier for the writer because of this sterling fact: if you've gotten an advance and your book flops -- that is, doesn't sell anywhere near ten times the amount of your advance, which means you don't "earn out" -- you're not expected to give the advance back. Of course, you're not likely to see another one at that level, either.