In this careful study, Gunter Stemberger reexamines the sources, history, and teaching of the Pharisees, Sadducees, and Essenes the three most prominent religious groups of first-century Judaism. Stemberger challenges old assumptions by asking the questions, What did we know from our sources? How reliable is the historian Josephus? Are the rabbinic texts direct witnesses to the history and teaching of the Pharisees? Was there any relationship between the Sadducees and Essenes? Can one really speak of religious parties/sects in first-century Judaism? The conclusions Stemberger reaches will spark debate among students and scholars of Judaism and New Testament backgrounds.