There are people who stay with one book, they buy the same brand over and over. They have found what works for them and they stick with it. Then there are the experimenters who try a new journal each time, the explorers always on the look out for something different, the librarians who have a couple of books going at a time. The Adjustable Bandolier is for them. You can fit a variety of sizes, or strap a couple books together.