I get intrigued by a puzzle, and writing a book is the best way to solve it.
If creative work protects a man against mental illness, it is small wonder that he pursues it with avidity; and even if the state of mind he is seeking to avoid is no more than a mild state of depression or apathy, this still constitutes a cogent reason for engaging in creative work even when it brings no obvious external benefit in its train.
So-called "inspiration" is no more than an extreme example of a process which constantly goes on in the minds of all of us.
