From a colleague who is a NT scholar:

In response to a question about 'Bible Codes':

I'm not sure which particular book on the 'Bible Code' you mean, -- there have been several in this vein. As usual there's a mixture of truth and error. The truth is that BOTH Hebrew and Greek alphabets functioned as number systems as well as alphabets when the Biblical texts were written. This means that the texts CAN be read as words OR as numbers, just as in the famous 666 text in Rev 13, which equals Caesar Nero in Hebrew, or the word beast, therion, in Greek; or how the name David can be read as the number 14 in Hebrew, hence the three 14s in Matthew's genealogy; or just as the name Jesus in Greek equals 888, 3 times wisdom, and so on.

The error in these Bible Code books (even when they're supposedly by Jewish professors of mathematics in Jerusalem, etc. etc.) is that they assume that they can do this for the whole Bible (or OT or NT) and get perfect mathematical results, thus proving once again the inerrancy of the Word of God (and also predicting the date of the assassination of JFK along the way! Why this should be such a test of true prophecy, I really don't know). In doing this, they assume that we have ONE stable text (in Hebrew and Greek) which can then be read as numbers with all sorts of amazing patterns and predictions emerging. In fact, of course, there are THOUSANDS of different Hebrew and Greek manuscripts and fragments, NO TWO OF WHICH AGREE in every respect, and some of which have whole chapters which differ (indeed, whole books differ, if we consider the Greek Old Testament). The Hebrew OT and Greek NT that we use as the basis of our translations today are scholarly reconstructions of what are thought to be the earliest readings, gathered from a whole array of manuscripts. We have no originals. We have no 'one text' on which everyone agrees (not even amongst the King James fans!). Of course, most of the variants are insignificant -- but they occur in every single verse of Scripture and make a huge mess of any 'perfect Bible Code' system.

So the basic premise of mathematical perfection residing in a particular text/version of Scripture is based on all sorts of ignorant assumptions about how we got those texts. Some of these guys are whizzbang computer and maths scholars, but it's a pity they didn't do an 'Introduction to the Bible' course.

So these books have a certain fascination for those attracted by the fundamentalist inerrancy heresy, but they have nothing to offer those who truly seek to understand God's Word.