How do you write a book?

There have been several people to ask me the question: "How do you write a book?" I suppose there are many ways to answer that question. I'm going to give you mine.

ME, AN AUTHOR?
I have always enjoyed taking a few days during a vacation to write. Often I'd simply begin writing the story of a person in some difficult situation. Usually I'd trail on for five pages, or fifty, then run out of time.

When I wrote The Runaway Pastor, it was much the same. I sat down one evening with the question on my mind: What would happen if a pastor ran away and hid from his life? What if?

And so I began writing. I finished writing the first few pages or so, and decided to keep them. Later that evening, I wrote a bit more. When prompted to name the file, I called it "Trent's Very Bad Day."

THE OBSESSION
Honestly, Trent's story became an obsession for me. I seemed to constantly wonder, "What going to happen next?" The story of The Runaway Pastor leapt from my mind one briskly written sentence after another. I couldn't stop the story or the characters. They kept acting. I kept writing.

And that is how the book came to be. That is how I best answer the question: "How do you write a book?"

SEQUEL?
I have begun work on a sequel for The Runaway Pastor. In fact, I have about seven starts. I like them all. But no one of them pesters me to keep creating. After writing about a chapter's worth, the characters seem to go away. I don't go to sleep wondering what will happen next.

MY PROBLEM WITH FOREKNOWLEDGE
And here is the ugly truth: Unlike the first book, I already know how this one will end. I know what will happen in the middle in order for that end to become reality. And I have several starts to get me on my way.

This knowledge defines my writer's block problem. For me, a story is exciting only so long as its conclusion is uncertain. Evidently, where there is no mystery, I am no author.

Looking for the mystery.