The first ever books in the world were the Egyptian papyrus rolls, which were composed of several columns of ancient writing scripts. The first of these manuscripts goes back as far as the 25th BC, and until the Christian era, they remained quite popular. However, during this period, the paper or the book industry underwent a transformation, and parchment started replacing the Egyptian papyrus rolls (more on Egyptian Papyrus Rolls on Wikipedia). Writing on parchments was arranged in parallel columns, and vertical lines were used to separate one column from another. This particular pattern gave rise to the idea of cutting the parchments into flat panels, which comprised of either three or four columns. Later on, this form evolved into the books we see today.