What is the author's tone in Genie: A Scientific Tragedy by Russ Rymer?

The tone of the book begins as a tone of impassivity. The author is presenting a story that can be somewhat dry, especially when discussing the history of linguists and the many different views of how a child comes to learn language. However, this tone changes to something close to outrage when the author discusses Genie's childhood and presents written examples from other people involved in the case, including Susan Curtiss and Jean Butler Ruch.