I love reading romance and reading about how to write romance. And writing romance, but really, that's hard.
This is a fantastic guide for anybody interested in writing romance, even if you're fairly new to the genre. I've read a fair number of writing "guides" that ended up needing a huge amount of knowledge about the genre, about terminology, about story structures, etc., but this is something you could read after having read all of three Harlequins and get a pretty solid understanding of romance.
I appreciate the emphasis on consolidating plot tropes and character tropes and subplots and etc., etc., in order to create the "fiction haiku." The exercises are fantastic for understanding this in greater depth, and just plain fun. (That's how you know you're a romance nerd, by the way--when you sit down for a half hour and just work through romance writing exercises for the fun of it, even without a story in mind.)
If you're interested in writing romance of any kind, you can get a lot from this book, regardless if you've written romance novels before. And if you're interested in writing category romance, it's even more useful.