Leveling the Classroom Library

As a summer project, I am leveling my classroom library.  As a fourth grade teacher, my class library was organized by genre.  I had colored smiley stickers on the spine of each book that corresponded with the color of the book basket.  Each genre had a different color sticker/basket.  Now that I'm moving to third grade, I have decided to level the books instead.  Each book will have a sticker on the front that has the level written on it, each level in a different color.  Books will be in matching basket color, of course.  Pictures will follow as the project progresses.