I recently bought Articy Draft to catalog my writing endeavours. It seems good for writing scripts, but what about writing a book?
I'm planning writing a novel using this tool. It's built primarily for game design (scripts and dialogs included). It's very useful for creating your universe's database and you can relate database items (like characters) inside your scripts, so you know when/where they are used. I thought it would be a good tool for coherence's sake.