One of the most common questions I get right now is whether I have finished the third book. The answer is a less than definitive, well, kind of. It's broadly done but my editor and I are still working on it and will be for a little while more.
When I start a book I have a very broad idea as to the premise and how the beginning, middle and end will work. However I don't outline chapter by chapter because what I've found over the years is that if I know every beat of the story I tend to get bored. If I'm bored writing it then I surmise that the reader will be bored reading it. True or not, that has been my belief. I may revisit my prejudices for the next book. It's a good idea to challenge your own prejudices from time to time.
The only problem with writing as I do now is that I tend to take some wrong turns. I'll try things out and see if they work. If they don't then I'll change them. What that does though is create a lot of continuity issues, which are time consuming to fix.
On the plus side I don't get overly attached to the material. I'm quite happy to cut whole chapters or sections if it helps the story. Hell, for Lockdown, I wrote an entire first draft of 80,000 plus words, which I threw out entirely because 'pretty good' doesn't do it for me and there are certain things I want to achieve.
As anyone who has read the books will know I burn through story. Fast-paced doesn't apply to the Lock thrillers. They are lightning-paced.
I want my readers ripping through the pages. I want to leave them exhausted. I want them ignoring the phone. I want them not showering or leaving the dishes in the sink. I want them staying up until all hours even though they have work in the morning. If that happens then the book has worked.
The problem is that to achieve that, for me at least, takes a lot of work. A lot of writing material that never makes it into the book. For the 85,000 words that the reader gets I probably generate double that, most of which no one ever reads, my editor and agent included.
And on that note I had probably better get back to work.