Raven Music is a very, very small company that specializes in producing scores and sheet music books of black metal albums and generally dark genres of music overall. The company has been periodically putting out books over the course of the past year, though I feel like I've been seeing the name mentioned more often than not lately.
So go to Raven Music's site and check it out! I personally think it's awesome someone is taking the time to sit down and transcribe great, bleaker albums for the masses to read through and interpret in their own way.
So far the company's catalogue consists of Emperor's In the Nightside Eclipse and Ulver's Kveldssanger and Shadows of The Sun, the latter of which is all arranged for piano, voice and general chordal arrangements. Seriously, how cool is that?