Libanius was a Greek who lived during the 4th century (ca. 314-393 CE). Never converting to Christianity, he was born in Antioch and taught rhetoric in Antioch, Constantinople and eventually returned to Antioch where he lived the remainder of his days. In his autobiography "First Oration" Libanius makes an interesting reference to a copy of Thucydides that was stolen and then recovered.
"148. Another occurrence deserves mention also. Although a trivial matter, it is significant. Some of you perhaps will regard me as a mere pedant, but I, smitten to my very heart, know that my emotion arose because of a calamity great indeed. I had a copy of Thucydides’ History. Its writing was fine and small, and the whole work was so easy to carry that I used to do so myself, while my slave followed behind: the burden was my pleasure. In it I used to read of the war between Athens and Sparta, and was affected as perhaps others have been before me. Never again could I derive such pleasure from reading it in another copy.By the fourth century, the roll had been supplanted by the codex. So Libanius is almost definitely referring to a codex format in this story. I find it interesting that his description of this copy of Thucydides closely matches the description of what scholars consider to be one of the earliest depictions of the codex by Martial in the first century.
149. I was loud in praise of my possession, and I had more joy in it than Polycrates did in his ring, but by singing its praises so, I invited the attention of thieves, some of whom I caught in the act. The last of them, however, started a fire to prevent capture, and so I gave up the search but could not but grieve at the loss. In fact, all the advantage I could have gained from Thucydides began to diminish, since I encountered him in different writing and with disappointment.
150. However, for this discomfort Fortune provided the remedy, a tardy one, admittedly, but, none the less, the remedy. I kept writing to my friends about it, so grieved was I, and I would describe its size and what it was like inside and out, and wonder where it was and who had it. Then a student, a fellow citizen of mine, who had purchased it, came to read it. The teacher of the class set up the cry, ‘That’s it,’ recognizing it by its tokens, and came to ask whether he was right. So I took it and welcomed it like a long-lost child unexpectedly restored. I went off rejoicing, and both then and now I owe my thanks to Fortune. Let him who likes laugh at me for making a mountain out of a mole hill. I have no regard for the laughter of boors." (Or. 1.148-150).
"You who wish my poems should be everywhere with you, and look to have them as companions on a long journey, buy these which the parchment confines in small pages. Assign your book-boxes to the great; this copy of me one hand can grasp. Yet, that you may not fail to know where I am for sale, or wander aimlessly all over town, if you accept my guidance you will be sure. Seek out Secundus, the freedman of learned Lucensis, behind the entrance to the Temple of Peace and the forum of Pallas." (Epigr. 1.2)Libanius's description of his copy of Thucydides gives insight into the value of books in the 4th century. Because books were hand made, each was unique and irreplaceable, like painting or sculpture. Books we're obviously very expensive to produce as a thief purloined Libanius's copy and was able to resell it for Libanius's friend was able to re-purchase the book in the market. Though very low compared to modern standards, literacy must have been high enough for there to have been a ready market for a stolen book.
Libanius Autobiography and Selected Letters, Volume I: Autobiography. Letters 1-50 (Edited and translated by A. F. Norman. Loeb Classical Library 478. Cambridge, MA: Harvard University Press, 1992) pg. 217-219.
Martial. Epigrams, Volume I: Books 1-7. Edited and translated by Walter C. A. Ker. Loeb Classical Library. New York: G. P. Putnam's Sons, 1919.