The author writes it

Every book starts with one person and a blank page. The author is the person who writes the words, and writing them is the first thing that happens - before the pictures, before the printing, before anyone else is involved at all.

The author's writing is called a manuscript. A manuscript is the story before it becomes a book: no cover, no pictures, just the words.

Authors rewrite a lot. Most finish a story, put it away, read it again and change it. Somewhere along the way the author usually writes the dedication too, the short message at the front.