Wikipedia: Keyboard

Piano and pipe organ keyboard (Can anybody add more information on structure, layout, size, history please?)

Computer keyboard: The keyboard is a device with many keys (usually containing the alphabet, the digits, and various extra keys.) After punchcards it became the main input device for computers. During the 1980s and 1990s almost all computers came equipped with it, and most users are familiar with it. There are different types of keyboard technologies. The layout of keys on the modern-day English keyboard is called the QWERTY design. There is another kind of computer keyboard known as chorded keyboard. Despite the development of alternative input devices such as the mouse, touch sensitive screens, pen devices, character recognition, voice recognition, and improvements in computer speed and memory size, the keyboard remains the most commonly used and most versatile device used for direct human input into computers.