Just finished. I've never read a single Stephen King novel (almost impossible, I know), as his topics and his style are just not "my" "type" of lit. However, having seen this particular book highly recommended in several diverse places, I borrowed a friend's copy. Besides, even if King's "his" was not "mine," it's certainly true that King's is "most's" if only by evidence of the fact that he's made a gajillion dollars with his words.
I almost put the book down after the first twenty pages because there was nothing about writing at all, just a memoir, and I didn't particularly care at all for another "how I made it big" life-story. Luckily, I flipped forward and found that the book was divided into two parts and it was from the second section that I began to read.
King writes very comfortably and directly in his advice and I was surprised to find such a friendly disposition to him. His main point that he stresses throughout is that a writer needs to read and write (as opposed to Hemingway's advice that all one needs to be a writer is to SAY he's a writer). Sounds simple enough, I know, but King pushes that message along convincingly and without hubris. Read and Write. No matter the genre. Read and Write. And along the way, he dispells with the so often heard advice of "write what you know." How can you KNOW anything about an alien spacecraft? Write what you WANT and then fix the holes in your rewrite. King puts forth his opinion that good stories are not created, they are found, like a relic, and dug up. It's in the digging that decides what condition the treasure is unearthed.
The added bonus to the book is his description of the horrific accident that nearly killed him. In this case, King IS writing what he knows and it's very touching. And though I've never read a novel of his, the incident seems worthy of the movies I've seen that were created from his books.
Leaving aside the first half of the book and all the descriptiveness of the obese baby-sitter who used to sit on his head and fart, five stars. I may even go out and read one of his books now.
EDITED 4/20/2013 TO ADD:
Now that I've read more than a handful of King novels, I've decided that this book must be classified as a work of "fiction" because King literally follows none of his advice in this fine book except for maybe suggesting that you write A LOT, which he does, A LOT.