Suzanne Collins. The Hunger Games. , Scholastic, 2008.

Each book in The Hunger Games trilogy has three sections of nine chapters each. Collins has said this format comes from her playwriting background, which taught her to write in a three-act structure; her previous series, The Underland Chronicles, was written in the same way. She sees each group of nine chapters as a separate part of the story, and comments still call those divisions "act breaks"