Hold On Tight Shelf by Colleen Whiteley

Either the books are too few or the shelf is too wide- you can never keep them from tumbling down like a stack of dominoes. Even if you put a heavy vase or a teddy bear up there- they can never quite stay straight just the way you want them to. This Hold On Tight Shelf can keep your reads up and tidy and you can always adjust it if you choose to expand or diminish your collection.