The author of the Anonymous Commentary on Plato's Theaetetus is unknown, a common practice for scholarly texts of the period. This philosophical work was written sometime between the late 1st century BCE and the mid-2nd century CE, a era scholars classify as Middle Platonism. The single, fragmentary commentary survives on a papyrus scroll discovered in Egypt, which itself dates to the mid-2nd century CE, proving the work existed by that time.

The author was an educated Platonist, likely a teacher or advanced student. The commentary provides a line-by-line explanation of sections of Plato's dialogue Theaetetus, engaging deeply with its questions about knowledge and perception. In doing so, the author also demonstrates knowledge of and debates with other philosophical schools like Stoicism and Skepticism. The exact date of the original composition is uncertain, but scholars suggest it was likely written in the 1st century BCE or early 1st century CE, as its ideas show no clear influence from later Neoplatonic thought.

This work is historically significant for several reasons. It is the oldest surviving manuscript of any text by Plato and the oldest existing commentary on his work. According to modern scholars, it serves as a crucial bridge, showing how Plato was studied and interpreted in the centuries between his own Academy and the later philosophical movements of the Roman Empire. Beyond philosophy, the papyrus is a vital document for understanding the history of the book, preserving a version of Plato's text that is centuries older than any copied in the Middle Ages.