I wrote a programming book back when tech books were a thing you had to go physically buy from a physical store (more than 20 years ago now). The publisher sent

I wrote a programming book back when tech books were a thing you had to go physically buy from a physical store (more than 20 years ago now). The publisher sent advanced royalties, which was money that was mine, free and clear (it wasn't a small amount either - certainly enough to compete with a full time salary for similar time commitment and knowledge/skills needed). I wouldn't see any more royalties until I'd sold enough to equal what my advance was. If I never sold enough, then I wouldn't see any new money - the original advance was still mine. I did end up seeing royalty checks, though not until the book was translated from English to Italian. For some reason, it sold comparatively well in Italian, pushing me over the threshold to earn royalities. The one actual royalty check I saw for my book was a grand total of $0.02. I never cashed the check and keep it in a desk drawer somewhere.