To carry along in your backpack or briefcase without any unnecessary big bulges. Seriously, if your presentation contains 20 or fewer papers, they'll nicely slide into these books (back to front, facing pages) and you can customize both cover and spine, a necessity these days. Your choice of black or white. Sometimes colors pop more vividly surrounded by black; at other times I prefer the light bright sensibility of my color-filled design against white; it depends on each client or potential client. In any case, these are a good price and from what I can figure out, a unique style of product.