One of the hardest — yet most important — questions an author often has to answer about his work is the one asked by this entry’s title.
Now, it’s not hard at all to answer, for many authors and even more books. When you walk into Borders or Barnes & Noble, when you browse Amazon, it’s all organized by “type”: romance along this aisle, SF over there, “literature” along the walls, and so on. The problem is that it’s these classifications which determine “what kind of book” a given title is — not the other way around.