(Heb. she'elot u-teshuvot, "questions and answers"). Written answers on issues of Jewish law and learning from talmudic scholars to queries from colleagues and lay people or communities. The practice of this form of rabbinical communication began in the talmudic period and became formally instituted in the geonic era.
When the Jewish people became dispersed, the problem arose of maintaining religious unity among the scattered Jewish communities. The practice therefore developed of referring halakhic queries to central authorities whose responses would determine local legal decisions and Jewish practice. Touching on all aspects of Jewish life, the responsa ensured a standardization of Judaism in all Jewish communities and constituted an authoritative body of precedents and decisions consulted to this day by rabbinical scholars when ruling on contemporary issues of religious observance. In addition, the sense of national unity was maintained by the constant flow of communications between the various communities. Not limited to practical matters alone, the responsa enabled scholars in remote areas to query colleagues in the centers of Jewish learning. Spiritual leadership could be maintained in remote communities and the sense of community among rabbinical scholars was reinforced, despite the vast distances separating them.
The responsa can be divided into three main periods:
a) Geonic (see Ga'on) (from the mid-seventh to mid-11th centuries). The first major responsa began to appear in the middle of this period. While some of the communications were brief answers conveyed in a word or two, others were more substantial, at times reaching the proportions of a monograph. The subject-matter was variegated, ranging from requests for assistance on issues of Jewish religious practice to queries on points rooted in Jewish as well as secular learning. These queries were directed to the Babylonian ge'onim, whose replies have become authoritative Jewish religious classics. Unfortunately, the ge'onim did not make copies of their replies and many have been lost.
b) Rishonim (from the 12th to 15th centuries). The subject-matter now focuses increasingly on issues of religious practice and the format becomes longer. These became regarded as authoritative sources.
c) Aḥaronim (from the 16th century to the present): In the wake of various Expulsions, Jewish communities became more scattered and less homogeneous. Problems arose concerning different customs and with regard to communal structures. The emphasis in terms of subject-matter was now on practical, rather than philosophical, matters.
As in earlier periods, the responsa of the 20th century, which are consulted by Orthodox, Conservative, and Reform scholars, rely on previous authorities---the Talmud and the responsa of previous centuries---in order to grapple with the problems faced by the modern Jew, such as organ transplants and euthanasia. Even during the Holocaust, Jews consulted rabbis to legislate on matters arising from conditions of coercion in the ghettoes and concentration camps. With the establishment of the State of Israel in 1948, Jews are now involved---after a lapse of 20 centuries---in all aspects of running a country and a new category of responsa is required in order to deal with halakhic issues within the context of sovereign Jewish statehood. Responsa are also studied today as a major source of Jewish social history, throwing light on the inner workings of the community and on everyday life.
Major projects of compiling and classifying the responsa have been undertaken by two of Israel's universities: the Hebrew University of Jerusalem and Bar-Ilan University, Tel Aviv, the latter by computerization.
