What the Gutter Takes

A book’s inner margin gets settled twice. The first time is a judgement about proportion, made on a flat screen with the text block in front of you. The second is arithmetic against a table published by whoever will print the book, and it can only be done once the page count is final. It is easy to confuse them. Neither step covers the margin the binding takes back, and no printer or platform we checked publishes a millimetre figure for it.