In the Ancient Hebrew script every letter in the Hebrew alphabet is drawn as a picture and carries inherent meaning. Aleph, from which we get "A", is drawn as the head of an ox and refers to a literal ox, strength, 1000 and clan or tribe. Think "strength in numbers." The two ideas are the same in Hebrew. Bet, the second letter, is drawn like a tent and refers to a literal tent, or home or going in or into something. In Hebrew gramar the letter bet is prefixed to a word to mean "in" or "into." Think "into the tent."
In Alexandria Egypt there was a Jewish scribal group who shortened the Hebrew Bible (Old Testament) from the standard 24 book form into a 22 book form, apparently to conform to the 22 letters of the Hebrew alphabet. They may have used the alphabet as a memory aid or an interpretive tool by matching the content of the books with the pictographic meaning of the letters.
A few years ago J.R. Church and Gary Stearman wrote a book called The Mystery of the Menorah suggesting the Hebrew letters match the books of the New Testament. They mapped the 22 letters to the New Testament books and reused 5 letters that have final forms to extend the alphabet to cover all 27 books. They did not alter the traditional order of the books.
The Bible has 66 books. If the letters of the Hebrew alphabet map to the books of the Bible it's unnecessary to extend the alphabet by reusing letters and it's unnecessary to shorten the length of the Old Testament by combining books. Just use the 22 letter alphabet 3 times to span the 66 books and see if it works. If the alphabet maps in a more compelling way to the books in Isaiah's order than otherwise then this study would also confirm the Bible's book order.