Peaceful
coexistence between
human beings and
machines requires clear
communication. The best
systems convey
information so elegantly that we hardly think about the
power they give us—
boundaries dissolve and we become one with our technologies.
The interface allows this. Common interfaces include the
remote control, the
stereo, and the
touch-tone keypad of a telephone. You see these interfaces not only on the products they were designed for, but also on things such as computer
software which has no "natural" interface of its own.
A good book about interfaces is
Interface Culture by
Steven Johnson.