If you're a Stephen King fan, this is worth reading, as it's about 50% writing advice, and 50% anecdotes. King talks about his early life as a writer, and in the last part of the book talks quite a bit about the accident that almost killed him a few years ago.
The writing advice itself is not bad (and King really is a fine writer, even if his books aren't to your taste), but it's nothing you won't find in any other book about writing, and it's rather light and general. So this isn't a detailed examination of the tools of the craft. King talks a little bit about theme and plotting and pace, a little about grammar and trimming those dreaded adverbs, and a little about how to get published and the value of an agent, but mostly this book is, as the title indicates, a memoir.