Why Book Page Numbers Typically Come In Multiples Of Four

Book page numbers typically come in multiples of four because of the way books are traditionally printed and bound. Here's why:

Printing and Folding: 
When sheets of paper are printed, they are often printed on both sides. These sheets are then folded in half, which creates four pages per sheet (two on the front and two on the back).

Binding: 
After printing, the sheets are gathered together and bound. The most common binding methods involve stitching or gluing the folded sheets together along the spine. Each group of folded sheets is called a "signature."

Consistency: 
To maintain consistency in the binding process, especially with modern printing and binding machinery, books are typically printed in multiples of four pages. This ensures that every sheet of paper contributes evenly to the book's structure when folded and bound.

Pagination: 
Pagination (numbering the pages) is straightforward when pages are in multiples of four. Each sheet of paper contributes to consecutive pages in a predictable sequence.

Efficiency: 
Printing in multiples of four is efficient in terms of both printing and binding processes. It reduces waste and ensures that the book's pages are neatly organized.

Therefore, while it's not an absolute rule, books generally have page numbers that are multiples of four to align with the practicalities of printing, folding, and binding in the publishing industry.