Who wrote the Bible?

Dear Rev. Know it all, 
Who wrote the Bible?
Sincerely,
Solomon “Sol” A. Scriptura

Dear Sol,         
First, the simple answer. A lot of people wrote the Bible, because the Bible is not a book. It’s a library. The word Bible comes from a Greek word (of course) “biblia.”  Biblia is plural. It means “books.”  (Biblion = one book, biblia =2 or more books) There are seventy-three books in the Bible, (unless you are Protestant, in which case you only have 66 books. Pity.)
There are a lot of sacred books in the world. Perhaps you are really asking “How did some books come to be regarded as uniquely inspired by Christians?”  It starts with the Jews, or rather with the Israelites, somewhere in the Sinai Desert. Sometime between 1450 and 1250 years before the birth of Jesus. A fellow named Moses led the Israelites out of slavery in Egypt through the sea to an encounter with God at the foot of His holy mountain. Moses went up the mountain and came back with the law given by God. So it seems that God, through the agency of Moses wrote the first the sacred books of the Hebrews, as the Israelites were also called.
Over the next thousand plus years, books of history, prophecy and religious poetry and parables were added to those first books of Moses. They were a loose collection of about forty or fifty books that were respected as inspired, some more than others. About 200 years before the birth of Jesus many, perhaps a majority of Israelites — now called Judeans, from which we get the word Jew — lived outside the Holy Land and no longer spoke their ancestral language, Hebrew.
Alexandria, a Greek speaking city on the Mediterranean coast of Egypt, had a large population of Jews. The king of Egypt commissioned a Greek translation of the Hebrew holy books. It was called the “Septuagint”, or the “Books of the Seventy.” The name comes from the legends surrounding the translation, something about 70 or seventy-two scholars, or perhaps 70 days necessary for the work of translation. We really know very little about the origin of the Septuagint. Still, the Septuagint became the authoritative canon of Scripture for Greek-speaking Jews, who quite possibly outnumbered the Jews who spoke Aramaic, a language close to Hebrew. (Just a word about “canon.” Canon originally meant a measuring rod. It is related to the English word “cane.” Anything that is a canon or canonical is considered normative, something against which other things can be measured.) 
The first disciples of Jesus seem to quote the Septuagint rather than the Hebrew original when they use the Hebrew Scripture and even the Qumran documents seem often to rely on the Septuagint rather than the Hebrew originals. So the Septuagint was very popular at the time of Christ. When the disciples went out into the Greek-speaking world, both Jewish and Gentile, they used the Septuagint as normative. The majority of Jews at the time of Jesus were probably Greek speakers, just as now the largest single group of Jews are English speakers. 
There were more than a million Greek-speaking Jews living in Egypt, while less than a million lived in the Holy land. There were perhaps 4 or 5 million Jews alive at them time of Christ, and practically none used Hebrew as a first language. For many of them, the Septuagint was the Bible, and when Christianity moved out of the Greek-speaking Jewish world into the Roman empire, they regarded the Septuagint as the Scriptures.
The first followers of Jesus didn’t have a defined New Testament, but the phrase used by St. Justin Martyr around 160 AD is interesting. He speaks of the “memoirs of the apostles.” It seems that what we regard as the 27 books of the New Testament took a while to develop, though they seem to have been in place a hundred years after Jesus. They were the texts that were commonly read at Mass by the early Christians along with the Septuagint. That’s probably how they came to be regarded as Scripture.
  At this same time, (@140 AD) a man named Marcion began to teach that the God of the New Testament was not the same as the savage God of the Old Testament. He also taught that the Old Testament Scriptures were not valid. He recognized only a shortened Gospel of Luke, and ten of Paul's epistles. All other writings were rejected. This is interesting in itself because it implies that as early as 140 AD, certain books were held to be uniquely inspired. In response to Marcion, the first Christians started to list the books that they held sacred.
By the early 200's, Origen of Alexandria probably used the same 27 books we now regard as the New Testament editions. The Muratorian fragment indicates a New Testament with four gospels. The Muratorian fragment is perhaps the oldest known list of the books of the New Testament from perhaps 170 AD. It claims to be a list of all the works that were accepted by the churches. There was still debate about the New Testament canon, but the major writings were accepted by almost all Christians by 200-250 AD.
In his Easter letter of 367, Athanasius, Bishop of Alexandria, listed the same books that we regard as the New Testament canon, calling them “canonized" along with the Septuagint, though he rejected the book of Esther. The Synod of Hippo, in northern Africa, in 393, approved the New Testament, as it stands today, together with the Septuagint books, as did the Councils of Carthage in 397 and 419. St. Augustine regarded the scriptural canon as closed, as did Pope Damasus I and the Council of Rome in 382. Damasus' commissioning of the Latin Vulgate edition of the Bible, c. 383, was instrumental in the fixation of the canon in the Latin speaking world. 
There is however, a fly in the biblical ointment. Christians were not the only ones worrying about the nature of the biblical canon. As early as Rabbi Akiba who died in 135 AD, the Jews were worrying about the exact text of scripture. Rabbi Akiba also believed that Simon bar Kochba was the Messiah and seems to have encouraged his revolt against Rome in 132 AD. In the Bar Kochba revolt, all Jews who professed Jesus as Messiah were expelled from the territory controlled by the revolutionaries.
Thus began the split between Judaism and Christianity that endures to this day, though at the time a great percentage, possibly the majority of Christians were ethnically Jewish or Samaritan. The Jewish scriptures and the Christian scriptures also seem to begin their rift at this time. The Christians accepted the larger Septuagint canon, but the followers of Akiba and the rabbinic Judaism he helped to found, rejected any book for which the Hebrew original was no longer in existence. These are Tobit,  Judith,  Wisdom,  Sirach, (also called Ben Sira or Ecclesiasticus) Baruch, 1 Maccabees,  2 Maccabees and sections of Daniel and Esther, 7 books plus the non Hebrew sections.
St Jerome did not think these books canonical, but he included them in the Vulgate, (Latin Bible) because the Church regarded them as canonical and had done so for three centuries. The current Jewish text called the Masorah, or Masoretic text (a Hebrew word meaning handed down), was finally completed and accepted predominantly  between the 7th and 11th centuries.
Martin Luther rejected the Catholic Canon of the Septuagint/Old Testament, in favor of the Masoretic text and attempted to remove the books of Hebrews, James, Jude and Revelation from the New Testament  because they contradicted certain Protestant doctrines such as Sola Scriptura and Sola Fide. His changes to the New Testament weren’t generally accepted among his fellow reformers. But, these books are still ordered last in the Luther Bible.
  There are more problems with the text of Scripture. Manuscripts have variant readings and there are disputes about translation and so on. What can one do to get the “true text” of the Bible? If you believe the reformation rule of Sola Scriptura, (Bible alone), you are up the proverbial creek without a text. But if you understand that these books are written by many human beings who were inspired by the Holy Spirit, you don’t really have a problem.
The question you asked at the beginning, “who wrote the Bible?” is really very easy to answer.  Around a hundred people wrote it. The more important question is "who chose these books as unique and sacred?" The Holy Spirit working through the ministry of the Church did that. She recognized these particular books as being uniquely “God-breathed” (which is what inspired means) and useful for learning the ways of God. The real author of the whole library is the Holy Spirit.
Remember what St. Paul tells us in 1 Timothy 3:15 “The church is the pillar and foundation of truth,” not the Bible. When there is a variant text, or translation, we have the unbroken tradition of two thousand years to tell us the exact meaning of those things that are doubtful. We had already been saying Mass for almost fifty years when the last parts of the New Testament were set down on paper, and, in a certain sense, it was Mass that created the Bible. It was at Mass that these books were publicly read and found to be uniquely filled with the Holy Spirit.
When you think about it, for Catholics, the Church is the mother of the Bible. For Protestants, the Bible is the Mother of the Church.
I hope this helps,

 Rev. Know-it-all