well if you take different versions of the bible ( the book i know best) you will find many many instances where words and phrases have been changed in each new revision of it.  One of the most startling that i remember from the 70's, when i was still investigating everything religious, in the orignal writing in aramaic and the greek translation there was a story about Lilith the woman who came before Eve and was not made from Adam's rib but made in the same manner Adam was.  And yet no other translations mention this it was edited out.  Although if i remember right there was for a time mention of it in the Catholic version.  Lilith and Adam did not get along and Lilith left the garden and then God made Eve.  There were several other major changes that i found out about at a bible scholars convention in washington DC in 1978 one was an aramaic word that was used in the original aramaic text .  This word appeared 900 some odd times and in all but about 3 or 4 times it meant soft as in a cloth being soft but in the 3 or 4 other times it was translated to have a base sexual meaning which did not fit the original text  and changed the entire meaning of the passage.  There was also a passage in genesis or leviticus or maybe exodus where the abominations unto god were listed and in the original aramaic one of these was being a coward but by the King James version the word had been changed to effeminate and in the new revised edition the word effeminate was changed to homosexual.  The current version of hell was first editted into the bible in the 1300s i believe when Dante wrote his poem The Divine Comedy the first part of which was the inferno until then there was no hell the way we know it today it was the eternal separation from god that was punishment.  my memory of all these is a bit faded since after i studied the major religions i came to realize that you have to suspend rational thought to believe them.  I chose to stay rational and accept the fact that until I come to the end of physical existence there is no way for me to know whether there is a god or any existence after this physical existence.  Once I reached this conclusion life became a whole lot easier for me as i put the issue out of my mind for the most part.  It would be a total no-sequitor for me except that it is pushed at me everywhere I turn, though it doesn't cause me mental turmoil anymore.  I really don't mind that other people can suspend rational thought and believe it I just wish they would quit trying to make me and everyone else feel guilty about not believeing.  
There is a lot of good teaching and ideas in the religious books of the world but they were all written by men and have been changed throughout their history some more than others and everyone of them has at one time or another been used for exactly the opposite reasons they were created for.  From what I have seen in my life religions has been used to teach hate and intolerance as much or more than they have been used to teach love and acceptance.  Even today some Islamist use their religion to make killing and terrorism acceptable to those who believe,  some christians use the bible to preach hate and prejudice and they both do it in the name of god.  This is not to say that either or any religion is bad, just that it is like all things in this world it can be used to uphold good and evil purposes as long as people blindly believe in it.
We must not forget that we are first a human animal and have to learn how to be a civilized Human.  religion can help you learn to be human and civilized, able to live and work together or it can be used to make you hate certain groups and be unwilling to let people think and act the way they feel is right.
the one thing I have kept from religion is this:

DO UNTO OTHERS AS YOU WOULD HAVE OTHERS TO DO UNTO YOU.

KEEP RELIGION OUT OF GOVERNMENT AND GOVERNMENT OUT OF OUR PERSONAL LIVES!

Thank you! Yes, you have made some valid points about what is being done by the followers of God. So let me address this first by way of a question. Have you ever told lies? If I murder someone does that make me a murderer? If you have lied that makes you a liar. Right? I can see a guy in prison for murder talking to another convict about another inmate being snitch, or the baby raper and what low lives they are. Darkness is heavy my friend. As for the things you can remember, I'm sure that those who have their own personal agenda will find what their looking for even if it means a little tweaking.
I do respect anyone who does an un bias study. Thanks again!

diya
ur question suggest that u are more concerned abt its being true or not that u dont risk ur time u gain the understanding of  holy books.

u are putting god here. do u know who is god?

so first make sure who is god. when u know who is god u would be abel to unfold the mystery.

so even if the said book are not to be true search the god u describe here.

do u believe that human being aint god.

first i would like to know abt the god from you.

what is god. did u know who is god, what shape is he or she?

fi ur answer is no. then did u serch fr god.

when u find him he will let u know by urself. and when u know him by urself u will write a book as well.

then u wont be confused at all.

Please, look from your heart, what feels best for you.  Let your heart, the love inside with the love of the Source, however you percieve it/him/ her and walk the path the is best for you following the teachings that keep guiding you to that place inside you which is beyond description.
One or all may hold the answers you seek at any given time.  You also may find many more places and times and people who will give you the gift of a piece of  the puzzle for YOU!!!
Follow the love, it will always guide you.
PS. It is the Love that is the Love of the Universe, of the Source, the Love that is beyond all other Love that will guide you.  You know it when you feel it, see it, hear it and it is always inside your "heart" for you, every moment of every day.
Have fun, enjoy the journey.

Well I suppose you don't have to use any Holy Scripture if you don't want to. First let me say that anyone practicing any religion from the heart, I have nothing but respect for you. There are some beautiful truths in all the Holy Books I think. To use any of them as infallible sources of history or science is a mistake that doesn't so the authors (or God)  of the works justice. How can we expect men, even inspired men, to know things that were utterly unknown at the time? History did not have the same meaning in the very ancient world as it does today. What we call legends were accepted as truth then. They were not subjected to the scientific method because that did not develop until around the time of Aristotle. Does this mean that they are useless lies? No not at all. Where the moral truths are found they have the same power then as now. But to expect perfect history or natural history out of these books, esp before 1000 BC, is really just unfair and unrealistic. It is trying to twist these lovely books into something they are not I would agree that the Koran, being the most recent book, would also tend to be the most historically accurate. The old testament and Bhagavad Gita would be less so in the modern sense of historical accuracy. This doesn't mean that I think that they are completely invented; just that they were not written in the way say "The Rise and Fall of Third Reich" was written (of course biases are always there). Of course in choosing a book as the basis of one's faith the first three would be infinitely superior to the last one. The power lies in the moral teachings.

I hope somehow there can be a reconciliation between religion and science. This would mean not demanding historical and scientific infallibility from the Holy Books at the basis of religions. I know scientific thinkers will never be able to accept the "young universe" for example. And why should they? There is so much evidence of some form of evolution over gigantic time spans, I really cannot understand how anyone could still not accept it. A hamster has a brain, legs, arms, teeth, basically all the same parts as a human, but a human is an utterly separate creation and has all these resemblances to even lower animals simply by coincidence.(having a special purpose would be a different issue) That is almost like saying that even though there are many parts of correspondence between my father and I, he was born, but I was created entirely separately. Why not just posit a Creator God who is responsible for this process? Do we know what is behind chemical reactions? Do we know why matter behaves as it does at the sub atomic level? My point is we can only go so far in our explanations before we arrive at the point of " because that is the way it works". God can be the intelligence behind it all.

And lastly to weigh in on my own choice of Holy Book. The Bhagavad Gita is very close to my heart. The wisdom in it does not depend so much on historical accuracy as on the power and the beauty of its language. The entire book reads the way the Beatitudes of the Bible read. Having said this, I must say that when any believer is reciting their Holy Book, there is a power that seems to transcend even meaning. I happened to hear recitation of the Koran on the radio once, and was completely transfixed, even though I know no Arabic at all. I have had a similar experience with Sanskrit, even before I learned the tiny bit that I know now. I have to agree with Srila Prabhupada, founder of the Hare Krishna movement- Holy Scripture is Holy Scripture-if it discusses the topics of God.