Expensive Typewriter was a text editing program that ran on the DEC PDP-1 computer that had been recently delivered at MIT. Since it could drive an IBM Selectric typewriter (a letter-quality printer), it may be considered the first word processing program, although it was not WYSIWYG, having no CRT display. It was written and improved between 1961 and 1962 by Steve Piner and L. Peter Deutsch.
In the spirit of an earlier editor, named "Colossal Typewriter", it was called "Expensive Typewriter" because at the time the PDP-1 cost a lot of money (approximately 100,000 USD).