Prof. Rachel Elior as quoted in Haaretz, March 13, 2009: "Sixty years of research have been wasted trying to find the Essenes in the scrolls. But they didn't exist, they were invented by [Jewish-Roman historian] Josephus. It's a history of errors which is simply nonsense," she said.
[http://www.haaretz.com/scholar-the-esse ... d-1.272034
]. Later she switched to Philo.
Translations of Josephus typically mention one "Essene" leader in the revolt against Rome, but this John may not have been an Essene. Abraham Schalit (in Namenwörterbuch zu Flavius Josephus, supplement to the Concordance edited by K.H. Rengstorf, Leiden, 1968, p.34, 46, 66) noted that Essa appears in Josephus as a variant reading for Gerasa, which, Schalit suggests, may indicate that John was not an Essene group member, but merely someone from Gerasa. "Vielleicht ist Essaios in B 2.567 als Ethnikon zu verstehen und mit Gerasenos identisch (vgl. Essa A 13.393 = 1 Gerasa). Dann waere 4 Johannes kein Essener gewesen!" (46)
Josephus mentions Judah the Essene (circa 104 BCE). Rather than this Judah being an invented person (in War and in Antiquities), he may be identical to the Qumran-attested "Teacher of Righteousness," for reasons given in "Jannaeus, His Brother Absalom, and Judah the Essene."