I'm interested in pre-medieval Mediterranean book copying.
There's a lot online about the book making process, but not much about the industry around it. Did it rely on companies distributors and stores, or academics and traders? Were there freelance scribes that worked out of their home?
I'm afraid I don't have time to weigh in with a response worthy of AskHistorians, but if the OP is interested, they may wish to consult G.W. Houston's chapter in Ancient Literacies: The Culture of Reading in Greece and Rome, entitled "Papyrological Evidence for Book Collections and Libraries in the Roman Empire," and P. White's (2011) chapter in the same volume "Bookshops in the Literary Culture of Rome."
They may also want to consult Starr (1987, pp. 213-223) "The Circulation of Literary Texts in the Roman World," in The Classical Quarterly, and Casson (2001, ch. 7) "Libraries of the Roman Empire Outside the City of Rome."
The Oxford Handbook of Papyrology (2011), edited by R.S. Bagnall is also a helpful resource.