Hecataeus of Abdera (or of Teos) was a Greek historian and sceptic philosopher who flourished in the 4th century BC.
Diogenes Laertius (ix.61) relates that he was a student of Pyrrho, along with Eurylochus, Timon the Phliasian, Nausiphanes of Teos and others, and includes him among the "Pyrrhoneans". Diodorus Siculus (i.46.8) tells us that Hecataeus visited Thebes in the times of Ptolemy I Soter, and composed a history of Egypt. Diodorus supplies the comment that many additional Greeks went to and wrote about Egypt in the same periode. The Suda gives him the nickname, 'critic grammarian' and says that he lived in the time of the successors to Alexander.
No complete works of Hecataeus have survived to our time, and our knowledge of his writing exists only in fragments located in various ancient Greek and Latin authors' works, primarily in Diodorus Siculus, whose ethnography of Egypt (Bibliotheca historica, Book I) represents by far the largest amount. Diodorus is mostly paraphrasing Hecataeus, thus it is difficult to extract Hecataeus' actual writings (see Carolus Müller's Fragmenta historicorum Graecorum). Hecataeus wrote the work "Aegyptiaca" or "On the Egyptians" (the same title of Manetho's later work), both suggestions are based on known titles of other ethnographic works, an account of Egypt’s customs, beliefs and geography, and the single largest fragment from this lost work is held to be Diodorus account of the Ramesseum, tomb of Osymandyas (i.47-50).
Diodorus (ii.47.1-2) and Apollonius of Rhodes tell of another work by Hecataeus, "On the Hyperboreans". Additional information on the Hyperboreans can be found in Strabo and Pliny the Elder, who might have their information from Hecataeus.
Though no name of a philosophical work by him is known, according to the Suda, the 10th century Byzantine encyclopedia, he wrote a treatise on the poetry of Hesiod and Homer, but nothing of them has survived. The Suda lists no other work by Hecataeus, also not a historical account of Egypt.
Regarding his authorship of a work on the Jews (utilized by Josephus in Contra Apionem), it is conjectured that portions of the Aegyptiaca were revised by a Hellenistic Jew from his point of view and published as a special work.