There are two important questions being addressed here:
1) - Is the Bible Authentic? I think it is probably about as authentic (in the sense of being a reasonable facsimile through translation) as any other documents from this era. As authentic probably as the works of Virgil, or the Chinese chronicles of their history back thousands of years.
2) - Is the Bible the infallible word of God? Here is the problem. The Bible is a great work of religious tradition, moral values, symbolic myth, and even poetry. It is the basis for one of the major religions on earth. However, there is a great deal of proof (to a rational viewer) that it can no longer be considered to be the literal truth (and thus not the literally true words of God). Even the Catholic Church has begun to acknowledge this/
Interestingly, the JWs have also - for example: They transcribed the biblical "days of creation" into first 7,000 years (with absolutely NO biblical reference proofs), later (confronted by scientific knowledge that 7,000 years is a hopelessly short interval for a creation epoch) - they say that are unknown but very long millenia in length. We just had a thread here that shows they have gone to extreme lengths to distort the story of Saul, the witch of Endor, and the spirit of Samuel - thus again saying (in effect) that what is written in the Bible cannot be interpreted as literal word-for-word truth.
Everybody today takes what they want from the Bible, ignores embarrasing or unscientific issues, and essentially makes up their own religious mind in the long run.