Here’s Merrymount’s rendition of an ideal page (left). It’s the opening of Henry Van Dyke’s Ships and Havens, and it’s a harmonious page. That’s to say, its proportional margins approach a certain timeless alignment. It appears the way books have been paginated since . . . well, since there have been printed books. J. A. Van de Graaf studied page layout. He graphed out years of early modern books. Gutenberg’s books. And he noticed that printers favored text blocks that looked exactly like the page it was on, only smaller (below). The rectangle formed by the text was proportional to its page in a ratio of two to three. 
At this point, without having to do any measuring at all, by merely drawing lines, you can position a text block on any page with margin ratios of 2:3:4:6.[1] It’s a canon of the page.[2]
It isn’t necessary, and a 2:3 ratio is often abandoned. It’s inadequate for paperbacks, for instance. Magazines won’t work this way. Still, it’s an enduring harmony, one which satisfies the eye the more you know about page design.
1. The 2:3:4:6 ratio describes margin space at the gutter, page top, page outside, and page bottom.
2. The canonical ratio of text block to page is a fundamental standard in printing. There are many other rules in print composition, not least of which is the marching order of book page layout, bastard title through colophon. Do you know what an “en dash” is?
This is essay number 34 of “Updike,” a printing history series.
