Josephus is an invaluable source for the history of Judaism in the Second Temple period. Louis H. Feldman offers the following comments on Josephus (The Anchor Bible Dictionary, v. 3, pp. 981-982):

Josephus was born in 37 C.E. and was given the Hebrew name Joseph ben Mattathias. His mother was a descendant of the Hasmonean family that had ruled Jerusalem a century earlier, and by birthright he was a priest. In Jerusalem he received a superb education, and at the age of 27 (in 64 C.E.) he led a delegation to the court of the Roman emperor Nero. Two years later he was pressed to serve as the general of the Jewish forces in Galilee in the revolt against Rome. He was captured and afterwards became a Roman citizen and pensioner of the Flavian emperors Vespasian, Titus, and Domitian. He is most widely known by the Roman name he then acquired, Flavius Josephus (or simply “Josephus”). In Rome Josephus resided in an apartment within the emperor’s house and devoted much of his time to writing. In part his works were addressed to his fellow Jews, justifying to them not only Roman conduct during the Jewish War, but also his own personal conduct in switching loyalties. However, his writings were also designed to justify Jewish culture and religion to an interested and sometimes sympathetic Roman audience. The earliest of his extant writings is the Bellum Judaicarum (or Jewish War), which was apparently drafted initially in Aramaic and then translated into Greek 5 to 10 years after the 70 C.E. destruction of Jerusalem. His second work, Antiquitates Judaicae (or Jewish Antiquities), was published more than a decade later; it was much longer, and recounts Jewish history from creation to the Jewish War, and contains some valuable historical information. His last two works, probably published shortly before his death, include the Vita (or Life), an autobiography intended primarily to defend his conduct during the Jewish War 30 years earlier, and Contra Apionem (or Against Apion), an apologetic defense of Judaism against a wave of anti-Semitism emanating from Alexandria. Josephus probably died ca. 100 C.E., several years after Trajan had become emperor in Rome. His writings, while generally ignored by fellow Jews, were preserved by Christians not only because they chronicled generally and so well the “time between the testaments,” but also because they contained specific references to John the Baptist, Jesus of Nazareth, and Jesus’ brother James.