There are four different basic grid types. These are simply the basic grid structures, and can be as simple or as complex as needed. The main consideration is that the grid should fit the content, rather than the other way around. The grid serves as a format for the content, and should act to make the communiction of the content better, not be an arbitrary organizational device.
The simplest to concieve of, and not what one neccessarily imagines when the term grid is used, is the manuscript grid. Also clalled the block grid, this grid uses one large block, usually for long or longer text documents. Novels are based on the manuscript grid. It need not be only delegated to text-only works, as shown in the second example, and it need not be boring.
These are two-page spreads, with letter-sized pages. The type is set in Myriad Pro regular 12/15, with a column width of 30 picas. As is hopefully apparent, this simple grid imparts a very clean, straightforward structure to the pages.