Why Are Books Always Rectangle-shaped?

For centuries, books have predominantly been rectangular, a shape so ingrained in our reading habits that we seldom question it. This format is not just a matter of tradition but a result of practicality, readability, and production efficiency. A rectangular book allows for an optimal line length, making it easier for readers to follow text without losing their place or straining their eyes. If lines are too long, our eyes struggle to track the next line, while excessively short lines force frequent shifts, disrupting the reading flow. Studies suggest that the ideal line length falls between 45–75 characters, with 66 being the standard, ensuring a comfortable reading experience.

The Evolution of Book Shape

In ancient times, people recorded information on papyrus scrolls or parchment sheets, which were typically read from top to bottom or even in multiple columns from left to right. As civilizations advanced, the codex format emerged—a significant innovation in bookmaking. The codex consisted of folded sheets sewn together along one edge, allowing for easier navigation and storage compared to cumbersome scrolls. Initially, early codices featured multiple columns per page, sometimes up to four, but by the fourth century, most had adopted a more compact format with only one or two columns.

However, these early books were considered luxury items, often large and heavy, requiring pedestals for support while reading. Over time, the size of codices was reduced, making them more practical for everyday use. As bookbinding techniques improved, the rectangular shape became the preferred standard due to its efficiency in both reading and production.

Practical Advantages of the Rectangular Shape

The rectangular form of books offers several advantages:

1. Ease of Handling: Rectangular books are easier to hold in one hand, making them convenient for prolonged reading sessions.
2. Efficient Use of Space: This shape allows for maximum text placement while keeping the book compact. It also enables books to be stacked neatly on shelves.
3. Economic Production: Standardized printing and binding processes work best with rectangular sheets, making mass production more cost-effective.
4. Better Page-Turning Experience: The width-to-height ratio ensures that pages can be flipped easily without awkward handling.

Will Books Always Remain Rectangular?

Despite occasional experimental formats, the rectangular shape has endured due to its historical significance and practical benefits. It has become deeply embedded in cultural norms, making it unlikely to change in mainstream publishing. While digital books and unconventional designs may offer alternatives, the classic rectangular book remains the preferred choice for both publishers and readers alike.

In essence, the rectangular shape is not just a design choice—it is a refined evolution of centuries of reading habits, efficiency, and convenience, ensuring that books remain accessible, readable, and functional for generations to come.