In the ancient world, a book could be produced either on a scroll or as a codex, which was made of folded sheets glued together, something like a modern book. One scholar has estimated the following variable costs (in Greek drachmas) of the two methods:

Another scholar points out that a significant fixed cost was involved in producing a codex:
In order to copy a codex ... the amount of text and the layout of each page had to be carefully calculated in advance to determine the exact number of sheets ... needed. No doubt, this is more time-consuming and calls for more experimentation than the production of a scroll would. But for the next copy, these calculations would be used again.
a. Suppose that the fixed cost of preparing a codex was 58 drachmas and that there was no similar fixed cost for a scroll. Would an ancient book publisher who intended to sell 5 copies of a book be likely to publish it as a scroll or as a codex? What if he intended to sell 10 copies? Briefly explain.
b. Although most books were published as scrolls in the first century A.D., by the third century, most were published as codices. Considering only the factors mentioned in this problem, explain why this change may have taken place.

Scroll 11.33 drachmas Codex 11.33 drachmas Cost of writing (wage of a scribe) Cost of paper 16.50 drachmas 9.25 drachmas