Alexander of Miletus, known as Alexander Polyhistor, was a Greek scholar of the 1st century BCE. Originally from Miletus, he was captured during the Mithridatic Wars, enslaved, and taken to Rome, where he was later freed. He became a teacher and composed numerous works in Italy, exemplifying the transfer of Greek intellectual culture to Rome in the late Republican period.

His prolific output, now lost and preserved only in fragments, covered geography, history, and ethnography. Significant titles include the historical work On Rome, the doxographical Successions of Philosophers, and the highly important On the Jews, a key non-Jewish source for Jewish traditions. He also wrote geographical works on regions like Libya, Egypt, and India, as well as works on marvels, a genre known as paradoxography.

Alexander’s significance lies in his role as a compiler. His encyclopedic works preserved vast information from lost earlier authors, serving as a major source for later writers like Pliny the Elder and Plutarch. His On the Jews was particularly influential for transmitting Jewish history into the Greco-Roman world, and his methodology helped shape Roman antiquarian writing.