Textual Criticism is the art and science of studying ancient manuscripts to find out what the text says from what the author first wrote a book, be it the Bible or other ancient writings.
For Christians textual Criticism is an important field both to know what God’s Word says and also as an apologetic.
There’s a lot of materials out there on the New Testament Textual Criticism, both in terms of books and internet resources.
There’s less for the Old Testament.
So below I have links to a three part audio series on MP3 on why we can know the words of the Old Testament are from the human authors (that is, it wasn’t changed). Check it out!