Firstly, there are numerous versions of the bible. The Christian Bible is divided into two parts, the Old Testament and the New Testament; some versions also have an Apocrypha section. The Old Testament includes all the contents of the Jewish Tanakh. In addition, Old Testaments published by the Roman Catholic and Eastern Orthodox churches contain 'deuterocanonical' books not found in the Tanakh, but which are found in the Greek Septuagint. The Catholic Church recognizes seven such books (Tobit, Judith, 1 Maccabees, 2 Maccabees, Wisdom of Solomon, Ecclesiasticus, and Baruch), as well as some passages in Esther and Daniel. Various Orthodox Churches include a few others, typically 3 Maccabees, Psalm 151, 1 Esdras, Odes, Psalms of Solomon, and occasionally 4 Maccabees. Evangelicals, and modern Protestant traditions, reject these books.
The New Testament relates the life and teachings of Jesus, the letters of the Apostle Paul and other disciples to the early church and the Book of Revelation. There are several ancient versions, the most important being Syriac, Ge'ez and Latin. The earliest known complete bible is the Codex Amiatinus, a Latin Vulgate edition produced in eighth century England (i.e. a full 800 years after Christ!). Most modern Protestant bibles are based on the 'Textus Receptus,' printed in 1550, which is the earliest edition with readings in variant manuscripts. A number of modern 'corrected' bibles incorporate more recently discovered 4th century manuscripts (Codex Sinaiticus and the Codex Vaticanus)
The use of chapters and verses were not introduced until the middle ages and later. Early manuscripts of the letters of Paul and other New Testament writings show no punctuaction whatsoever. The punctuation was added later by other editors, according to their own understanding of the text. (Punctuation can shape and change the meaning of a passage.)
The bible has been translated many times over - it was originally written in Biblical Hebrew and Aramaic. Sometime in the 2nd/3rd century BC the Torah (Genesis, Exodus, Leviticus, Numbers, and Deuteronomy) was translated into Koine Greek.
From the 800s to the 1400s, Jewish scholars (Karaites Masoretes) compared the text of all known Biblical manuscripts in an effort to create a unified, standardized text. A series of highly similar texts eventually emerged, and any of these texts are known as Masoretic Texts (MT). The Masoretes also added vowel points to the text, since the original text only contained consonant letters. This sometimes required the selection of an interpretation, since some words differ only in their vowels— their meaning can vary in accordance with the vowels chosen. In antiquity, variant Hebrew readings existed, some of which have survived in the Samaritan Pentateuch, the Dead Sea scrolls, and other ancient fragments, as well as being attested in ancient versions in other languages.
On top of this, the bible has been translated more recently into most world languages. The first english translation was the King James I bible. The King ordered a team of scholars and the best poets in the land to translate the bible so as to preserve its beauty: it is therefore not a rigorously accurate translation. Furthermore, there are words and concepts that cannot be translated. For example, the Bible talks about "The Word;" this is inaccurate. The literal translation from Greek is "eon" or "age."
When Christians were being persecuted by the Romans, a level of secrecy was maintained. Portions of the New Testament, such as Paul's letters, are therefore vague and even coded in places! The references to 666 being the number of the devil, are actually a reference to the Emperor Nero (Christians could not talk openly about their dislike for him at the time)
When Christianity later became the official religion of the Roman Empire, it was 'altered' a little to make it more palatable to the Romans and other conquered peoples. For example, the image of Mary holding the infant Jesus was introduced as a replacement for (the egyptian) Isis holding the infant Horus, and Mary took the place of the 'Mother Goddess' of the Pagan and Heathan religions, and the female Roman and Greek goddesses.
The Vulgate (that 800BC bible) was compliled at the Pope's insistence, to be in line with early Synods.
More recently, Roman Catholiscism has been altered again to become Voodoo (not recognised by the Vatican) and the less extreme Mayan versions (which are accepted by the Vatican).
The Gospel of St Thomas is hotly debated - the Coptic version found in 1945 at Nag Hammandi (there are earlier fragments found in 1885, the significance of which were not realised) were dated to around 340AD (and the greek fragments to around 200AD). It is unclear why it was not included in the Bible - it may have belonged to a branch of christianity outside that which compiled the bible, it may have just been superceded by the other New Testamant books, or (quite likely) it may have been deemed heretical. My favourite quote (which has made it to Wikipedia, for my convenience!) is:
114. Simon Peter said to them, "Make Mary leave us, for females do not deserve life." Jesus said, "Look, I will guide her to make her male, so that she too may become a living spirit resembling you males. For every female who makes herself male will enter the kingdom of Heaven."
There are also quotes condoning equality for Gentiles - what would the KKK have to say about that?!
The danger of religion
Being a good little... atheist... I shall stick the metaphorical fox amoung the pidgeons by referencing some of the ideas from my own upbringing: Religion is one method of reinforcing the concept of a patriarchal / heirarchical society to people. When we learn our place in society as inferior to God, and the all-knowing preachers and clergy (who have more than a little influence on world politics), we learn not to argue with our superiors in all walks of life. We allow ourselves to be exploited in low-end jobs, because we believe we do not deserve better. We do not debate with our teachers, and in many sad cases, we do not always believe we need or deserve a good education. We lead our lives according to societies' norms, and we allow ourselves to be discriminated against - how many women, even now, take traditionally feminine jobs or play house-wife because it's expected of them? (And how many end up on anti-depressants?!) We glibly believe leaders who tell us that homosexuality, contraception, abortion, drinking alcohol and political subversion are condemned in the Bible (when, in fact, the Bible does not specifically comment on these things, and even supports some of them!) We do not question when our politicians pass immoral legislation (the holocaust, aparteid,...) and we do not question when we are sent to fight another man's war in God's name.
Now, I know that's an exteme view - and I know many religious people who are very intelligent and socially-conscious. But religion can be (especially historically) used as a tool, and it's writings are therefore inherently biased.
Testing Historical sources
When we assess any historical or scientific source, we ask a standard set of questions. In their most simple form, the four W's and a H: What? Who? Where? When? and How?
What? A collection of ancient texts, the oldest of which are fragments written on papyrus scrolls and similar, in ancient Hebrew and Aramaic. Many of the storys in the old testament are similar to ancient Babylonian legends (for example, the story of Noah). Large portions of the bible were handed down in an oral tradition, before anything was written - they may easily have changed in the telling. The original scriptures did not contain vowels, and were not punctuated, and were therefore open to interpretation from the start.
Who? In the case of the old testament, we simply don't know. Some books are attributed to biblical figures, but this is often debated by scholars. It is known who wrote large parts of the New Testament, but we don't know a lot about them! There are also some misnomers about the authors - for example, many people mistkenly think that the four gospels were written by the four disciples of the same names. The scholars compiling the original bibles would have had their own agendas.
Where? The bible was written in the Middle East. References to the 'Great Flood' are thought to refer to an immense flooding of the Tigris and Euphrates in ancient times - to someone living in that area, it would indeed have looked as though God had flooded the whole earth! The laws in Levitcus on what you are allowed to eat make perfect sense when you consider the dangers of eating old sea-food in a hot environment, or the fact that wild pigs would have been riddled with tape-worm. Biblical references must therefore be taken in context.
When? The earliest consolidated versions of the bible date from 800AD - that's 800 years after Jesus walked the earth, and significantly later than any of the occurences in the Old Testament. In that time, the spirit of Christian teachings probably changed quite radically.
How? Due to the time elapsed in consolidating the Bible, there are probably untold volumes of scripture that just got lost or forgotton about, or edited out because it was not in keeping with what the authors wanted to portray.
In conclusion, the bible (or bibles!) really doesn't stand up as a historical source. Granted, there isn't a whole lot of evidence from old testament times, and some parts can be cross referenced with other ancient legends and archaeological finds to deduce something. But I wouldn't take it literally.
That's not to say it isn't a beautiful piece of writing, inspired by God and providing valuable insight into Judao-Christian religions