“The Ultimate Display” is a paper written by Ivan Sutherland in 1965. In the paper, Sutherland describes his vision of the ultimate display, which would be a room where a computer can control the existence of matter. For example, a chair displayed in this room would be physically usable, handcuffs would be confining, and a bullet would be fatal. Sutherland suggests that with appropriate programming, this display could create a virtual Wonderland similar to the one Alice encountered in the famous story.
This concept of the ultimate display was quite visionary for the 1960s. Three years later, Sutherland actually created a prototype of a head-mounted three-dimensional display, which further demonstrated his ability to go back and forth between abstract ideas and concrete implementations. This prototype is discussed in the paper “Going Back and Forth between Abstraction and Concreteness.”
You can find more information about “The Ultimate Display” in the original paper by Ivan Sutherland and an article about it on WIRED. Additionally, details about the head-mounted display prototype can be found in the proceedings of the Fall Joint Computer Conference in 1968.