Yes, it is.
There are often other ways to express the same meaning, but as it stands, your sentence is perfectly correct.
One answer objected to 'all day long' and suggested just 'all day' instead. While that would certainly be correct, there is nothing wrong with using 'all day long', which adds emphasis.
Please note too that a sentence can be grammatically correct even when it doesn't make sense (though yours does). There is NO need for there to be any explanation of what the book is, from the grammatical point of view.