By genre

It looks easy at first glance. Sure, fantasy there, science fiction there, crime there, mainstream there. But it isn't easy.
*Yes, I like to complicate things. Welcome to my blog ;)

First: whose definitions? Is it horror just because it has vampires? Is it crime just because someone is murdered? Is it fantasy just because there is something not rationally explicable - and is it a realistic novel just because there are no dragons?

Second: How wide or narrow definitions of genres? Subgenres is a wonderful jungle to explore. There's urban fantasy, but there's also paranormal investigators, paranormal romance, and fantzy (a.k.a. kick-ass chick-lit urban fantasy). There's alternate history, but then there's e.g. steampunk, and branching off from that, bustle punk and dieselpunk.

Of course, there are genres in mainstream as well, let's not forget. A friend of mine, Guru Wonganamapetilapilo, brilliantly invented the genre "Big books with dubious content". Ulysses is a perfect example of this genre, and I add authors like Thomas Pynchon and Georges Perec (all favourites. In fact, the genre is a favourite of mine). This can be completed with the genre "Small books with dubious content". Then there's the genre with the Swedish name "akaporr" - academia porn. E.g. The Secret History. Other mainstream genres could be "boyhood", "girlhood", "family novels spanning three generations", "small town books", "man pondering the world with himself as beginning and end", and so on and so on.

Every book fits into at least one genre. And that's another complication - complication in a good way, of course - the genre-mixing and genre-reinventing books.

I think this system would need to be associative. A chain of similar sub-subgenres. Could be fun! And then you could make a map. Like the one of Fiction Island in One of our Thursdays is Missing by Jasper Fforde.