Note: Mathematica Notebooks are structured interactive
documents that are organized into a sequence of cells. Each cell can
contain different types of material such as text, graphics, or
Mathematica expressions. When creating a document, you must
indicate what type of material is in each cell or the system will read
it all as Mathematica expressions. This is quite simple to do
using the main menu on the Notebook.
Some typical cells defined in notebooks include: