Booking Through Thursday asks:
What’s the most helpful book you’ve ever read?
I think that would probably be one of the books on writing I've read over the years... though I'm not sure I could pick just one. And, also, you'd have to define what you meant by "helpful". These books have been great for honing the craft of writing... but they haven't been so great for my reading life; now I tend to nitpick and I'm really hard on the books I read because I tend to spot the "errors".
Some of the books that I've found "helpful" are:
You Can Write a Novel by James V. Smith, Jr. - It's a great one for getting everything together so you can sit down and get something on the page.
The Writer's Journey by Christopher Vogler - It uses Joseph Campbell's work as its basis and builds on it with concrete examples from popular culture. This is also an interesting book for readers, since it teaches about story structure. (You'll never be able to read a book or watch a movie the same way after reading this one!)
Writing Down the Bones by Natalie Goldberg - Its little snippets of wisdom are great for inspiration!
On Writing by Stephen King - It's funny that I've yet to read one of his novels, but I've read his book about writing novels! He's got some great advice in here, along with some biographical material that makes for interesting reading. Every writer should have a copy of this one!
What's the most helpful book you've ever read? Tell me in the comments!