Mice and trackballs are members of a class generically described as pointing devices. All pointing devices have the same purpose—allowing you to move the cursor (or pointer) around the screen and to click to select items or perform other functions. A great variety of fiendishly clever pointing devices are built into notebook computers, but nearly all desktop systems use mice. Those few that don't use a trackball, which is essentially a mouse turned on its back.
All modern mice and trackballs are optical, which provides better precision than earlier mechanical models and eliminates the need for cleaning. Don't even consider buying a mechanical mouse or trackball, no matter how little it costs.
Use the following guidelines when choosing a mouse or trackball:
Mice are available in various sizes and shapes, including very small mice intended for children, small mice intended for use with notebooks, the mainstream ergonomic mouse, and some very large mice that have many buttons and extra features. Most people find nearly any mouse comfortable to use for short periods, but if you use a mouse for extended periods small differences in size and shape often make a big difference in comfort. Pay particular attention to mouse shape if you are left-handed. Although makers of asymmetric ergonomic mice may claim that their mice are equally usable by left- and right-handers, many lefties find them uncomfortable and so resort ...