Shotgun approach --> hit or miss
I used this book as a way to refresh my perspective on a mystery novel after finishing a second draft. I highlighted perhaps a dozen relevant/useful passages in the entire 300-page book. There are a handful of interesting ideas, but the biggest challenge I encountered is that the quality of the advice is entirely dependent on the author of each chapter - so, if what you want to learn about happens to have been written about by an average advice-giver, you're out of luck. For a better treatment - more concise and productive, and of better quality throughout - consider Hallie Ephron's "Writing and Selling Your Mystery Novel."

Great Help
I have other books concerning this subject. What I like about this book is that it contains chapters by different authors. There is nothing like hearing advice from the very authors that you enjoy reading so much.

The ultimate resource for Mystery Writing
Mystery Writing is an art in itself. It requires a lot of planning and preparation in order for the mystery story to work. Planting 'red herrings' and false clues in a story is an art that novice writers will have trouble in achieving with their first attempt. That is the reason why this book is so good -- it brings together the creative geniuses in the field of Mystery writing -- and these writers tell you their secrets to producing mystery. Definitely worth the money.

Wide ranging and helpful
I found the book to a helpful review of everything from the unwritten rules of writing a mystery through the submission process. Personally, I enjoyed having different people present their views. I can see that it might be annoying if you want just one point of view. My advise is to read whatever section you are interested in and skip sections that you do not care about. Good job!

Having to mine isn't necessarily a bad thing
While I agree with the previous poster that one has to do a certain amount of mining with this, and other Writer's Digest anthologies, I don't think that's necessarily a bad thing. I actually had an opportunity to talk about the book recently with Sue Grafton, who edited it, and she said her goal was to take readers from idea through publication, employing the voices of experts in each area. For example, the chapter on series characters is written by Sara Paretsky, whose V.I. Warshawski is a classic demonstration of what she's talking about. In all, I enjoyed and appreciated the disparate voices perhaps more than I might have appreciated the same advice in a monolithic voice.