Old Testament
The Old Testament is a collection of different biblical books comprising the Jewish religious scriptures. In Judaism it is called the Tanakh. Christians embrace the Old Testament as part of their holy scriptures, which, together with the New Testament make up the Bible. Christians have a different viewpoint than Jews in that they see the Old Testament giving prophetic references to the coming of Jesus Christ. Versions from ancient times exist in both Hebrew and Greek including the Dead Sea Scrolls giving a very ancient snapshot dating back to the time of Jesus.
The Old Testament documents the creation of the world by God, and the tribulations and errors of human beings, in particular His chosen people the Israelites. Following the history of the Jews from their earliest patriarchs to their enslavement, freedom, becoming a nation, period of the judges, ruled by kings, splitting into two nations, and eventual conquest. It continues until about 400 B.C. when God's chosen people have once again been allowed to return to the Holy Land and have come back to the worship of the Lord God. From the writing of the earliest five books, which is traditionally ascribed to Moses, to the last, is believed to be a period of about 1,000 years. The New Testament doesn't pick up until 400 years later with the story of Jesus.
The Canon of the Old Testament was fixed by Judaism in the 1st century A.D. and is the same Old Testament found in Protestant Bibles (except for ordering and naming conventions.) Other branches of Christianity include the Apocrypha. Most Old Testaments go back to the earliest Hebrew translations, but the Greek Orthodox church uses the earliest Greek versions.