I finished reading the book. Very nice job. It would be a bit difficult for the average high school physics student, but would be perfect for the student doing a science project involving optics. I think it would also be appropriate for the college student doing an optics project. Given the amount of time usually given to optics, even in basic college physics, it would probably be more than needed. But it certainly should be a great resource for anyone needing to learn the geometry of light rays and lenses. I teach advanced placement and honors high school physics and I can see this book as useful for our more advanced students.