I recently joined a new library. I didn't know my way around yet so I went and examined the little chart on the wall to try and find the genre I was in the mood for, and it occurred to me that I didn't have a really good handle on what a 'genre' actually was. Listed on the chart were things like Science Fiction, Romance, Horror, and Young Adult, but those all seemed like they were answering different questions to each other.
Science Fiction, like Fantasy, is defined by what reality the book is set in. Romance is a story (essentially boy-meets-girl), as is Crime. Horror is neither of those things... it's an emotional response. Young Adult is even worse... it's defined by who might read it, which is pretty silly given that YA books are read by people of all ages.
So when I got home I started playing around in Scapple to try and figure out a way of understanding genres in my head. The starting point I took was that every book will be categorisable in 3 ways: Reality, Story and Emotion (I'm dismissing things like 'target audience' as bigotry rather than genre classification).
The trouble is, I'm far from an expert in a lot of categories. The PNG file linked below is where I've gotten to (full size available to download at the end of this post). I'd love any help and knowledge the fine members of this forum have to share.

I've put a few well known books in the middle to help illustrate how the three questions fit together.
Please feel free to tell me where I've made terrible mistakes, or to suggest any additions in response to any of the three areas. For example, are there established sub-genres of the Romance story similar to what I've done with Crime? Remember that things like "Paranormal Romance" and "Romantic Comedy" aren't a sub-genre of Romance stories in the above definition, merely a combination of a Story (Romance) with either a Reality (Supernatural) or Emotion (Humour) respectively. That's not to say that established combinations like those aren't worth noting - they are. If I can come up with a neat way to represent it, I'd like to start mapping the combinations of the three questions as well. Some of those combinations have been dumped unceremoniously in a box in the corner for the moment. Feel free to comment on those too.

I'll continue to update my Scapple Map as the suggestions come in, and when we've reached a sensible conclusion I'll go through to re-order, restructure and make a really pretty updated map and share it here.
You can download the PNG file here.
So, whad'ya reckon? Any thoughts?