Old Testament = Jewish Torah for the most part. This is what Yeshua (PBUH) lived by (you folks do realize he was a Jew... right?)
New Testament = Book largely written by Saul of Tarsus (aka Paul the "Apostle"), founder of the Christian Church, and a man that never met Yeshua (PBUH), unlike the original Disciples.
The King James version of the Christian Bible is one of several translations/interpretations of the texts with the necessary books removed from the original canon of the Bible (i.e. detailed accounts of Yeshua (PBUH) as a child).