Book excerpt: Never before has a book been published that describes the techniques and technology used in writing text editors, word processors and other software. Written for the working professional and serious student, this book covers all aspects of the task. The topics range from user psychology to selecting a language to implementing redisplay to designing the command set. More than just facts are involved, however, as this book also promotes insight into an understanding of the issues encountered when designing such software. After reading this book, you should have a clear understanding of how to go about writing text editing or word processing software. In addition, this book introduces the concepts and power of the Emacs-type of text editor. This type of editor can trace its roots to the first computer text editor written and is still by far the most powerful editor available.