The Talmud is a record of rabbinic discussions pertaining to Jewish law, ethics, customs and history. The Talmud has two components: the Mishnah, which is the first written compendium of Judaism's Oral Law; and the Gemara, a discussion of the Mishnah and related Tannaitic writings that often ventures onto other subjects and expounds broadly on the Tanakh. The terms Talmud and Gemara are often used interchangeably. The Gemara is the basis for all codes of rabbinic law and is much quoted in other rabbinic literature. The whole Talmud is traditionally also referred to as Shas (a Hebrew abbreviation of shishah sedarim, the "six orders" of the Mishnah).
Origins of the Talmud
Originally Jewish scholarship was oral. Rabbis expounded and debated the law and discussed the Bible without the benefit of written works (other than the biblical books themselves.) This situation changed drastically, however, mainly as the result of the destruction of the Jewish commonwealth in the year 70 C.E. and the consequent upheaval of Jewish social and legal norms. As the Rabbis were required to face a new reality—mainly Judaism without a Temple and Judea without autonomy—there was a flurry of legal discourse and the old system of oral scholarship could not be maintained. It is during this period that Rabbinic discourse began to be recorded in writing.
The earliest recorded oral law may have been of the midrashic form, in which halakhic discussion is structured as exegetical commentary on the Pentateuch. But an alternative form, organized by subject matter instead of by biblical verse, became dominant about the year 200 C.E., when Rabbi Judah haNasi redacted the Mishnah.
1 -[The Talmud : Biography]
2 -[The Talmud : The Mishna]