> Second, using your compression technique, we'd still need to have some numbering on the volumes, and to describe a book, we'd have to do so by a list of numbe

> Second, using your compression technique, we'd still need to have some numbering on the volumes, and to describe a book, we'd have to do so by a list of numbers describing which volumes comprise it and in what order. Yes, for a normal library this would be the case. But this library contains every possible book. So the index list you're asking for, describing which volumes comprise what book in what order, is the complete list of all possible orderings of volumes up to the maximum book length. You don't really need that list, because you know exactly what it looks like. But then, you don't really need the volumes either, because you know what they look like too (being all combinations of N bits). So yeah, you'd just need a 0 and a 1. I already got a copy of that library, and the cool thing is that it doubles as a light switch.