Scroll to Codex Transition

The design of the new Biblioteca Alexandrina suggests a merge of the scroll and codex formats in a context of digital access. Can this classic format contest, between the scroll and codex, be repositioned in a larger perspective of composite reading modes?
Roger Bagnall, Professor of Classics & Professor of History at Columbia University, spent a week with us in Iowa City. He took time to participate in our class and took time to relate to all the non-papyrologists out in this province of the book studies Imperium.
Among his lectures was one on the scroll to codex transition. In a very orderly and rich presentation he discussed the inadequacies of all the various technological and literary explanations for the transition.
While there is no argument that the codex supplanted the roll across a period of five centuries the explanations neither avoid contradictions nor add together into a convincing composite. The codex format was more economical, but the economy of duplex writing was somewhat off set by loss to gutter margins. Random access is somewhat facilitated by the codex format, but skilled reading manipulations were well developed in both roll and codex reading. Judaic injunctions for and against the use of the scroll or codex suggests an explanation for the codex preference for pre-Christian works, but does nothing to explain an equal transition, which Roger pointed out, of preference for the codex in classical literature. Finally, new literary genres such as Gospels or Letters do not particularly favor either format or do layouts for accommodation of commentary and these factors really emerged at a later period anyway.
So what is up here? How can a transition equivalent to that from print to electronic transmission go unexplained? Maybe it goes unexplained for the same reason that our current transition is unexplained.
Roger Bagnall suggested that an important clue is in the evidence that while sectarians adopted the codex exclusively the classical world did as much by adopting the codex in place of the scroll. In other words a more universal explanation of a greater magnitude is at work. He suggested a change of reading mode.
Now this brings up a curious question. Do books predate reading?
The reading environment of late Antiquity was still one teetering between a majority tuned to orality and a minority even aware of the option of written transmission. The scroll exemplifies this environment and perhaps exemplifies the reading format of non-readers. The scroll was absolutely associated with recitation and spoken delivery. The codex, however, may exemplify a new reading mode for writers rather than listeners and most importantly may exemplify a transmission format for exchange between writers. A clue here may be the papyrus letter of late Antiquity both in its folded format and in its emergence as an extended exposition and literary genre.
These folded letters were the medium of choice for avid sectarians scattered over the Roman Empire, but connected by the network of continual Mediterranian navigation. These letters were written, read and copied constantly. Their folded impositions and security stitching immediately suggest the codex format.
Now this is beginning to make sense. The reading modes overlay and merge with each other. These are the modes of orality, writing, print and electronic transmission. They all emerge, persist and influence each other in a continuing, timeless dynamic of the storage and transmission of knowledge. Meanwhile another pattern of technological and literary production is at work. Here various media express the state of the interaction of reading modes at particular periods. The scroll to codex transition would be one of the earliest, while any television to WorldWideWeb transition would be a later example.

What is the Book?
The book is not an elephant. We discussed this in class. It is more like a mammal, or an overarching abstraction. In this pliant discussion it spans many media and all reading modes. Roger Bagnall also warned us of this overlay of the definition of a book as a subject distinct from the scroll to codex transition.
(fourth century Kellis farm account book in-situ)