The history of responsa in Judaism (Hebrew: שאלות ותשובות, Sephardic: She'elot Utshuvot, Ashkenazic: Sheilos Utshuvos, usually shortened to שו"ת Shu"t), spans a period of 1,700 years. Rabbinic responsa constitute a special class of rabbinic literature, differing in form, but not necessarily in content, from Rabbinic commentaries devoted to the exegesis of the Bible, the Mishnah, the Talmud, and halakha (the codes of Jewish religious law). The codes themselves contain the rules for ordinary incidents of life. The responsa literature covers all these topics and more.The mode, style and subject matter have changed as a function of the travels of the Jewish people and of the development of other halakhic literature, particularly the codes. Formulation of responsa, or she'elot ve-t'shuvot, which literally translates to questions and answers, generally involve an individual or group asking either teachers, rabbis, or heads of yeshivot about halakhah (Jewish law) and the party responding via an exchange of letters. Responsa literature spans 1700 years and there are even responsa being developed based on questions posed today. The development of responsa literature can be divided into six periods: the Tannaitic Period, the Geonic Period, the First Rabbinic Epoch, the Second Rabbinic Epoch, the Third Rabbinic Epoch, and the Fourth Rabbinic Epoch. Source: Wikipedia (en)