Source: touchscreens.com (http://www.touchscreens.com/images/main.jpg)
A touchscreen is a combination of a computer monitor and an easy-to-use input device. Using a touchscreen, a user can operate devices such as PC’s, communication devices, public terminals, etc., without a keyboard, mouse or any other input device. To make selections, user presses buttons that appear on the screen directly by using fingers, pointing pens or even toes and prostheses. The surface of the screen is touch-sensitive and can provide the computer with information on the exact location on the screen where a touch was made – very much the way a mouse sends signals to the computer.
Touchscreens can be used as assistive devices by users who lack skills to use classic computer equipment. With touchscreens, use of devices becomes more natural, intuitive, and user-friendly
Most touchscreen equipment is shipped with adequate kit and software. However, specific or additional software may be required depeding on the operating system being used. Also be sure that your computer has the type of port required to connect to the touchscreen.
Note that not all types of touchscreens react when not touched with bare skin (capacitive type requires a conductive input) and that there are differences in picture quality (surface acoustic wave type is best).
For many, positioning of the touch screen is key to it’s use, for instance; flat on a surface rather than upright. Be aware of this issue when buying
17-inch touchscreen add-on (kit for adding touch functionality to a classic monitor): around € 200
17-inch flat LCD/TFT monitor with surface wave touchscreen, USB interface: around € 1,000