“The grid is a regulatory system which pre-empts the basic formal decisions in the design process. It’s preconditions help in the structuring, division and ordering of content.”
Mark Bolton’s ‘Five Simple Steps’
Image from Texas Tech University System
In the context of graphic design, a grid is an instrument for ordering graphical elements of text and images. Grid-based design can be particularly useful in creating sites that are predictable therefore easily navigated, and visually appealing. Grids are a useful starting point at helping designers to plan where things go, and make it easy for site visitors to use.
An article in Smashing Magazine discussed this further and explained more about how our minds relate to rhythm and pattern. It explains how pattern recognition allows the human brain to store similar or identical impressions (such as primary shapes or colours) in a pattern library and retrieve them for quick analysis of new stimuli. This is the reason why we don’t look at individual letters when reading, but instead recognize whole words at a time (by pulling previous instances of the same pattern from our memory bank). It’s also the reason why we instantly recognize letters themselves such as the alphabet “A,” “B,” “C,” even if the font, size and colour vary the basic shapes are stored in our pattern library in our memory banks.
The article also goes on to explain how the mind also has the opposite effect when pattern or rhythm isn’t followed. Any stimulus that doesn’t match any of your existing pattern records will prompt a new entry in the memory bank, which, in turn, requires more brain processing power. This is where the importance of design structure and grids, whether horizontal or vertical, comes in. This method of thinking and processing I believe proves that Grid systems are indeed a beneficial aid to design and how we process information.

Image from WebDev-il
However many have said grid systems can stifle creativity and cause uncreative boxy looking sites and can over aid creativity by providing a framework that already answers some design questions such as where to place elements or how wide should the measure be? etc. A well-designed grid system will assist in answering a lot of these questions and more and make designing pretty simple. Aesthetics can be measured and more importantly can be constructed. Using a grid allows you to immediately experiment with type areas, shapes and harmonious compositions. You can explore how type and image will work together on the various types of grid layouts using wireframe applications Wireframe, photoshop or any design program and ready designed grid systems or tools such as 960 grid system or yalm.