If Anne Lamott's Bird by Bird is the mother of all books on writing instruction and the writing life, then Stephen King's On Writing is the father of all books in that genre.
Bird by Bird is written with a mother's touch- loving, artistic, humanistic and intelligent, while On Writing is relentless, stern, and wildly captivating. It's part memoir, part writing insight that is enjoyable even if you have no aspirations to write.
It's easy to see why King is such a literary legend after learning about his life long love of the craft and strict writing regimen. On Writing is on the mark; classic nonfiction by one of the best fiction writers around.