The first hand written draft of my book is finished, and so for the past couple months I've been typing the second draft. Of course, as I've typed it, I've also made changes on the way. I had an idea to add more depth to it, change scenes, and add more life to my characters as I've typed it, but something changed. As I near the end of the draft I realized the nature of the book evolved into something else in my head. Now I want to go back to the beginning and make even more changes. The scenes are the same but the expressions are completely different. The overall tone I had in mind is completely different than originally intended. Its better actually. The book feels more grounded and deeper. Not in a form of a message, just the undercurrent that drives the book is more pronounced. So my question is, does this happen to a lot of writers? The tone of their book changing drastically. Also how often do writers change the tone of their books? And overall is it a good sign? Or just a writer can't seem to make up their mind?