(Apparently in his school, there are Apple Books and Orange Books. Apples being fruits that you have to eat in one sitting, starting from the outside and going sequentially toward the core. Oranges, so long as you peel them, can be taken one wedge at a time, and in any order, and the wedges will keep, unpeeled, for quite a long time without oxidizing, so you don't have to eat it in one sitting. When I probed more deeply, I found that this is how his school discriminates between fiction books, which must be read chapter to chapter, in order, and non-fiction books, which may be referenced and order isn't important.)
You know, I find that division of books into apples and oranges to be quite charming. That would make an anthology of short stories or poems an orange book unless the individual items were laid out in some sort of thematic order or were part of a shared continuity. So it isn't a strict fiction/non-fiction correspondence.
However wouldn't Banana Book be a better term for an Apple Book? There isn't any reason you can't take a bite from one side of an apple and then take the next bite from the other side. However, a banana needs to be eaten in a linear sequential order.