p.s. Here's another thing that might be interesting for people with side projects: I just checked my royalties. When I wrote CoffeeScript Ristretto, I estimate

p.s. Here's another thing that might be interesting for people with side projects: I just checked my royalties. When I wrote CoffeeScript Ristretto, I estimated that the market for JavaScript Allongé would be 10x as large. Obviously the market for JavaScript was more than 10x as large, but there are way more JS books, and my particular style of writing seemed like it would fit the kind of early adopter who would use CoffeeScript in those days. Looking at my royalties today, I see that all editions of JavaScript Allongé have generated approximately 6x as much in royalties as CoffeeScript Ristretto. You could take the line that I should have sold way more JavaScript Allongé. Or, you could take the line that CoffeeScript Ristretto outsold my estimate. For various reasons, I take the latter view: You can be surprisingly successful in a smaller market, with fewer competitors, that has a very "opinionated" or "early adopter" culture, compared to a mass market with many competitors and a wide variety of sub-cultures.