A while back I finnished Stephen Kings book, "On Writing". wiki link

I read it mostly because it was the only book I had access to at the time, and the fact that I've never liked any of Stephen Kings books didn't make me more enthusiastic. But the fact was that the book was a writers treasure chest. He's an extremly sharp technical writer and knows exactly why he writes every single letter, and has no trouble transmiting this information in the book. The most helpful for me was the huge number of very practical advice on things not to do.

He also had very practical advice on how to translate visual images into text and how to make believable dialog. He also goes into the subject of getting published, and getting paid which is helpful for aspiring authors.

I'd like to hear about any other good books that focus on the task of writing. All advice is good advice.