The Genre Structure series looks at the elements that make fantasy, science fiction, and horror what they are. They include short stories that serve as examples. All three volumes are Gold Best Sellers, and they all have high ratings and good reviews.
They’ve been in the RPG Dollar Store for a while. On 1 September 2021, they’re going away forever. While they remain excellent reference books, they don’t reflect the Dancing Lights Press vision going forward. To start, they’re heavily skewed toward how fiction is structured. That’s useful to know when writing tabletop roleplaying adventures, but I can say that this is 100% a roleplaying product.