The original canon of the inspired Scriptures - the Hebrew Tanakh - was fixed and accepted without question by the Jews before the time that Jesus walked the earth. The next major event in their theological timetable was well understood to be the coming of the Messiah - although they had little understanding of his purpose. The apostle Paul then later made clear that the various letters written to the early Christian congregations by himself and various other apostles had also been inspired by God's holy spirt, and were therefore to be read as holy Scripture, along with the later gospels of Jesus's ministry, and the book of Revelation which looked far ahead to the restoration and new order. The Christian Greek scriptures quote directly from the Hebrew scriptures literally scores of times, as support for the points made.
Much later on, however, the corrupted and valueless Catholic church fathers deliberately and wrongly added to the canon a number of apocryphal books (Tobit, Judith, 1st & 2nd Maccabees) which are simply collections of popular myths, have little historic and absolutely no religious value, and simply confuse the whole issue. These, however, still appear in the Catholic Jerusalem and Douay bibles today.
The New World translation of the Bible rendered and published free of charge by Jehovah's Witnesses worldwide since the 1950's, and based directly on the original King James (Authorised) version of 1611, is universally accepted to be the finest modern-English translation available, taken directly from the Greek Septuagint texts that Paul himself and the apostles used, long before they were re-translated back into the original Hebrew.