Along with the other two books I'm "consulting" right now, I've added "Writing the Popular Novel" by Loren D. Estleman. He's been around for years as a western and crime writer, and I haven't read as many of his books as I'd like to. In particular, I now want to read "Bloody Season", which is his novel about Tombstone, Wyatt Earp and the OK Corral.
Estleman has a direct style, and his book warns you that you'd better be serious about writing - his routine is five pages a day. I like the little quotes at the end of each chapter, and one talks about how Agatha Christie killed off both Hercule Poirot and Miss Marple in books that were published after her death, thus ensuring that no one else would be able to write novels about them. Not that that would stop anyone these days (that's why the prequel was invented) but apparently no books have been published with Poirot or Marple in charge.
This, of course, would just add more fuel to those who are placing bets that Harry Potter will die in Book 7.
Back to Estleman - one of the points he makes is about relying on the internet for accurate information. His comment about those who believe vows of accuracy: "any credentials posted on a Website are liable to come from the same bozo who posted the misinformation in the first place." That gives you an idea of what the book is like! Down to earth and direct. And useful.