When you are a writing a book, do you know how the book will end or does it direction unfold during the writing?

The whole idea of being a creative writer is to be unpredictable to himself. You start with an end and if you stick with it then story does not have room to expand. It's always better to have a sketch of the story but when it asks you to go out of that sketch, don't be afraid to do so.

It happens both ways. Sometimes we start with a skeleton in mind but after proceeding we concieve a more brilliant idea to present our work. So we change the original skeleton in total. But sometimes we start in a planned task and finish it with the same.