This document defines and explains the key elements of a typographic grid, which is a graphic structure that aims to organize information into a more readable format. It discusses the margins, flowlines, modules, spatial zones, columns, rows, gutters, folios, running headers/footers, and markers that make up a typographic grid and help guide the eye across the page to structure text and images. The grid uses these various elements to break up space and impose structure in a visual balance.