"Gradually the book in codex form superseded the papyrus roll. The literary codex was already known in the first century A.D., but in the second century more than 98% of the Greek literary texts which we possess were still written on rolls (the percentage might have been notably lower outside Egypt, but there is no specific reason to think so). In the third, fourth and fifth centuries the figures sink to 81%, 26% and 11%, respectively. One group in Egypt, however, had already long given its allegiance to the codex: the Christian biblical papyri of the second century, which are few (eleven are now known), are exclusively from codices. From roughly 300 A.D. the total production of literary texts in Egypt declined markedly, and those that were produced were mainly in codex form.
In order to understand this change we have to consider these two phenomena together: the overwhelming preference of the Christians for putting their holy books into codex form, and the much slower decision of those who wrote and commissioned non-Christian writings to change to the codex, a decision made during the last decades of the third century and the first decades of the fourth. [...] the suspicion must remain strong that the Christians saw some other specific advantage in the codex form, and, as others have suggested, this is likely to have been the greater ease with which a particular passage can be found in a codex. To find the passage which you want to read to the faithful or use against your opponent in a theological squabble, you would commonly have had to unroll up to ten feet of papyrus. How much easier to mark a page and turn to it immediately! It is interesting that in the lists of second-century codices that are unconnected with Christianity or Judaism, of which seventeen are currently known, six or more are texts which may have been needed for consultation and quotation more than for ordinary reading. Some are also texts which are likely to have been wanted in "one-volume" editions, such as Plato's Republic. Thus the codex had a number of advantages over the book-roll, and it should in general have made it easier for people to read literary texts. It certainly made it easier to look things up in a technical handbook, or in a legal textbook or in a collection of enactments such as was to be found in the new legal codes of the 290s. The victory of the codex over the book-roll was natural in an age in which religious books were gaining in relative importance, and in which consultation and quotation instead of independent and disinterested reading were becoming commoner.
The copying and the practical availability of secular literary texts underwent a decline which probably started in many places in the third century."
[William V. Harris, Ancient Literacy (Harvard 1991), 194-95]
‘Could a rule be given from without, poetry would cease to be poetry, and sink into a mechanical art. It would be μóρφωσις, not ποίησις. The rules of the IMAGINATION are themselves the very powers of growth and production. The words to which they are reducible, present only the outlines and external appearance of the fruit. A deceptive counterfeit of the superficial form and colours may be elaborated; but the marble peach feels cold and heavy, and children only put it to their mouths.’ [Coleridge, Biographia ch. 18]
‘ποίησις’ (poiēsis) means ‘a making, a creation, a production’ and is used of poetry in Aristotle and Plato. ‘μóρφωσις’ (morphōsis) in essence means the same thing: ‘a shaping, a bringing into shape.’ But Coleridge has in mind the New Testament use of the word as ‘semblance’ or ‘outward appearance’, which the KJV translates as ‘form’: ‘An instructor of the foolish, a teacher of babes, which hast the form [μóρφωσις] of knowledge and of the truth in the law’ [Romans 2:20]; ‘Having a form [μóρφωσις] of godliness, but denying the power thereof: from such turn away’ [2 Timothy 3:5]. I trust that's clear.
There is much more on Coleridge at my other, Coleridgean blog.