The document discusses the history and development of touch screen technology. It begins with Dr. Samuel Hurst inventing the first touch sensor called "Elograph" in 1971. It then discusses the four main types of touch screen technologies: resistive, surface acoustic wave, capacitive, and infrared. For each type it provides details on how it works and its advantages and disadvantages. It concludes with a comparison chart of the technologies and an overview of the advantages and disadvantages of touch screens.