Thesis statement to "Lies my teacher told me" by James Loewen

It is not quite clear to me whether you are asking for a thesis statement for an essay you would write about this book or if you are looking for what the book's thesis is.

The book's thesis is that American history is taught poorly.  This is because the books are filled with facts rather than ideas and because the books are too, essentially, conservative.

If I were writing an essay about this book, my thesis statement would be something like this:

Although James Loewen is right that history is taught poorly, I do not believe that the solution is to replace what he sees as conservative excess with his own excessively liberal ideas.