They are essentially your window into your computer. Monochrome monitors show your text and graphics in one color, usually white, green or orange against black for the IBM PC family, and black against white for the Macs. The Mac Classic is now the only current model that has a built-in monochrome monitor. With all other Macs and all IBM PC clones, you select a separate monitor. If your work is fairly simple, and you are not using a lot of color, stick with monochrome.
Monitors also come in a variety of sizes.
If you plan to include scanned black and white photos, you should consider a gray scale monitor that will enable you to see a maximum of 256 different levels of gray. Page layout programs enable you to combine a variety of text and graphics into one document. ReadySetGo and QuarkXpress are examples of two levels of complexity in page layout software. A third type of program is excellent for long documents such as books and manuals. For elementary purposes, a word processing program may be sufficient.