Yes, it's for commercial reasons - There are two people who will buy the book. Those who read the blog (and who will hopefully buy it no matter the title), then there are those who have no idea what a blog is but who stumble over the book in a bookshop. The idea is to give them a better idea of what the book is about. Of course, at the moment there is a big picture of an ambulance on the front, although that may change...