We hear people say that the Bible is "unreliable and has been changed over the years." Let's look at these claims.
There have probably been more scholars, most of them smart and very well educated , who have studied the history and text of the Bible than any other book or collection of writings in existence. What is really amazing is that most of the scholars have broad areas of agreement, and the differences found in manuscripts of wildly divergent places and times are very, very small in comparison. Breakthroughs have come from archeology over the past two centuries; more and older manuscripts and pieces of manuscripts have been found. We now have literally tens of thousands of documents and partial documents of the New Testament from those first few centuries. The most dramatic story, of course is the Dead Sea Scrolls--a collection of writings that were found in the area of the Dead Sea and surrounding areas in 1947 and later. Upon very serious study, which is still continuing, it was confirmed that these scrolls date from before 150BC, and contain at least part of almost every book in the Old Testament. What is significant is not only are they about a thousand years older than the oldest manuscripts known before this discovery, is that there are very few differences, none significant, between these writings and the later ones. They do clarify some readings and shed light on the historical and cultural background of their times. Other archeological finds from the Greek and Roman periods recently found, not only of Biblical writings but a variety of contemporary writing, have been important in understanding the Greek, Aramaic, and Hebrew languages of the period. One thing I find interesting is that there are so many other very early writings--commentaries and related documents--that quote the New Testament that it would be possible to reconstruct almost all of the text just from quotations in these writings. And again, these very early witnesses demonstrate how essentially accurate what we have is, and that the text was basically agreed on within the first few centuries of the Church.
The whole study of translations is for another day, but for now I will say that scholars' understanding of the ancient languages, the number of available sources, and the constantly changing modern languages are factors that have led to the explosion of translations over the past hundred or so years. I like reading different translations, and find that each helps me understand what God has been saying to His people for at least four millenia.