P.OxyOxyrhynchus: A City and its Texts, Virtual Exhibition: Scribes and Scholars
Book Titles and Tags: Second-third century AD
Ancient books had no spines. Instead, many of those from Oxyrhynchus and elsewhere came equipped with tags made of papyrus or parchment, called sillyboi which were glued or tied to the outside of the roll and allowed the book to be identified at a glance while still stored in a capsa (kibotos), a container for papyrus book-rolls (click for detail):
wall painting from Pompeii: Museo nazionale, Naples
There survive about a half dozen published such tags, most of them from Oxyrhynchus. Cicero refers to them with the spelling sittybai in his letters to Atticus (Ad Att. iv 8.2, iv.5.4). The tags were attached to the back of the roll, hanging down, with the title on the tag facing outwards, as seen in this wall painting from Herculaneum (click for detail):
Example 1 / Example 2 / Example 3 / Example 4 / Example 5