Good Readers and Good Writers, Tone?

In my opinion, the authors tone changes throughout the essay. In the beginning, he starts out with a defensive tone. He is describing how you cannot go into a book with a predetermined idea of what you are going to feel while reading. He is defending the authors of the world. He also explains how you need to have an open mind. His tone changes to a more informative and less defensive tone. He begins explaining what you need to understand when reading or writing. Also, he describes qualities needed for proper understanding of a story. He describes these qualities in ways that require you to think while you read. He asks you to choose from a list of ten qualities, and decide which you should acquire before attempting a new story. As we come to the end, we reach a more understanding and explanatory tone. He writes in a question then answer form, which makes me feel like he really wanted the readers to understand the point he was trying to get across. He no longer seems to be overly defensive, but also still informative at the same time as being explanatory. The tone he gives off through the entire essay kept me wanting to finish.