Many books of the Bible existed and were transmitted orally before they were eventually recorded in writing. This may seem strange to us today, however, in a society in which most people were illiterate, as in biblical times, the oral tradition was heavily relied upon.
One of the techniques that was used to help people remember long passages is evidenced in the first story of creation in Genesis, chapter one. The division of creation into seven days, each following a pattern of God speaking, God creating, and God blessing, made it easier for people to listen, retain, and retell the story. Eventually, each book of the Bible did come to be recorded in writing, however, without a printing press, which was invented in the 16th century, the mass production of books was impossible. Until that time, believe it or not, most Bibles were copied by hand! When Constantine lifted the ban on Christianity in the 4th century, he authorized production of copies of the Bible, by hand. Because this was such an arduous task, it was rare for the average person to conceive of owning their own copy of the Bible. Instead, people looked to their priest who was often one of the few literate people in the community, to possess a Bible from which he could proclaim the Good News.
In the Middle Ages, the task of producing copies of the Bible was embraced by the monasteries. For many monks, the copying of Scripture by hand in rooms called Scriptoriums was their chief task. By the late Middle Ages and the rise of universities, book copying became a profession. Still, only the very rich could afford a copy of the Bible that was hand-copied, most-often in Latin. Stained glass windows and wall paintings in the churches often told the stories of the Bible for ordinary Christians who could not read.
With the invention of the printing press in the mid-15th century, it was now possible to mass produce the Bible, eventually making it conceivable for the average Christian to own his or her own copy in their own language. Today, the Bible is readily available, not only in print, but also online. You can check out the New American Bible, the translation that Catholics used at Mass, at http://www.usccb.org/nab/bible/index.shtml.