“Ancient Bookbinding.”

Papyrus_ScrollThe 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. 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.
Books have been part of the world since the early ages, and so the need to bind them together has also been present since then. In the olden days, a much different binding concept was used than what exists today.
The Egyptian papyrus rolls were stored in a tubular binding. The parchments were also often wrapped up in a roll, and secured with a ribbon.
However, when parchments started being cut into paneled forms, the binding also evolved. The new binding was more convenient to use and remained durable for longer than the tubular form. As such, it became the preferred choice.
In the beginning, the paneled parchments were hinged along any one of the edges, and were bounded with stitches or a lacing.
The columnar arrangement of writing was prevalent even at that time, particularly so for the Latin books.
Generally, the Romans used three to four columns to separate content on a single parchment. This style has been transferred down the generations, and exists even today.
Several published papers, journals, textbooks and reference books have pages that have been divided into two or three columns. Adopting this style makes the text easier and quicker to read.
There are also many books which differ from this, and consist of only a single column. As such, their sizes are also reduced so that the text becomes more legible.
via i.bookbinding.com