Thesis on Ishmael

I am required to write a 3-paragraph essay on Daniel Quinn's book Ishmael. My instructions say that I have to write a thesis that either defends or attacks the book. In my thesis, I want to defend this book. I do not know how to state the main idea of this book, and my paper while also defending the book. If someone could give me a suggestion on how to refine my thesis, or just critique it, that would be much appreciated. Here's what I have so far:

Daniel Quinn's Ishmael does not rewrite history, but rather looks at it in a different and impartial perspective. It shows the pattern in history and suggests that the solution for the future is that rather than wait for change, the people have to be the change.