The Bible, it is commonly said, is made up of smaller units called books. This somewhat oversimplifies things.
Let’s start with the New Testament, because the situation here is a little simpler. The New Testament is considered to consist of twenty-seven books, starting with the four gospels. These little biographies of Jesus come to about 60 to 100 pages, if we figure 250 words per page. Once you’ve read your way through the four gospels, it would seem reasonable to say you’ve read four books. Then comes the Acts of the Apostles, and it too seems to be a book.
All the rest of the Bible, though, is letters. Some are pretty big, running over twenty pages. But they generally get shorter as you go along, with the second to last book being Jude, which fits comfortably on an 8-1/2 by 11” page of single-spaced type. Here’s a PDF of it: jude.pdf.
Can we really say Jude is a “book”? Sure we can. We might try to define a book here as a “single recognizable text found in any of the various anthologies commonly known as the Bible”.
But now let’s go to the Old Testament. Let’s leave aside the Catholic and Orthodox Old Testaments, and just look at the Protestant Old Testament. According to the table of contents in a Protestant Bible, there are thirty-nine books. Now, the Protestant Old Testament is made up of the same works that are found in a Hebrew Bible. How many books in the Hebrew Bible? Go to the table of contents, which is where the end would be in an English Bible, and there you will find that this is composed of twenty-four books. What gives?
A careful comparison will show that the Protestants have two books in some places where Jews have just one. Thus, the three books of Samuel, Kings, and Chronicles are in Protestant Bibles 1 and 2 Samuel, 1 and 2 Kings, and 1 and 2 Chronicles. It’s the same stories — even the same sentences, in the same order — just that the Jewish Bible has a book called Samuel that contains all the material found in 1 Samuel and 2 Samuel in a Protestant Bible, and so on for Kings and Chronicles. Likewise, the Jewish book of Ezra contains everything found in the Protestant Ezra, but then follows it up with everything contained in Protestant Nehemiah. The biggest difference in count comes from the twelve minor prophets. In Jewish tradition, they make up a book called The Twelve. In Christian traditions, each prophet gets his own book. It’s the same material in the same order, just different book-counting conventions.
I apologize, in advance, for casually referring to any and all of these works as “books” of the Bible.