Outlining Your Novel by KM Weiland
I thoroughly recommend this for all fiction writers. It will strengthen the foundation of any story.
This book explains why putting a comprehensive outline of all of the parts of your story together before you start writing, is important, and DOES NOT kill the spontaneity for those free spirits (pansters).
There were lots of great examples and helpful insights by other well known authors. I wanted to actually use this process before I wrote a review, and this is what I found.
I didn't always work through everything in the order it is in the book, but kept going back-and-forth, nibbling away at problems until I found the gem of an idea that resonated with me. It showed me the difference between thinking I know my story well, and digging deep to unravel to real core of the plot and my characters.