The document discusses the organization and structure of grids in document design. It defines different types of grids including column grids, modular grids, grids by image, and hybrid grids. Grids introduce order, help distinguish information, aid navigation, and allow efficient layout. While grids provide structure, designers can vary or violate the grid based on the specific document's content and purpose. The overall goal is to make the invisible grid structure visible in serving the message and reader experience.