Interesting fact: Crime fiction outsells SF and Fantasy combined by about 3:1. (If I was purely focused on making money by writing fiction, that’s where I’d be. (But one word of caution: writing crime is a lot harder and more specialised than I realized before I tried it. It’s got the research requirements of hardcore physics-driven hard SF, combined with the characterization requirements of literary fiction, and your plotting had better be bulletproof or it just won’t work. (Hint: write the first 90% of the book, with lots of random clues and characters. Then go back, re-read it, decide who Did It, delete contradictory evidence, and write the end.)))