A genre that mostly features shiny, shirtless men on its covers and sells ebooks for 99 cents a pop might seem unserious. But at stake are revenues sometimes amounting to a million dollars a year, with some authors easily netting six figures a month. The top authors can drop $50,000 on a single ad campaign that will keep them in the charts — and see a worthwhile return on that investment. In other words, self-published romance is no joke.