The Tcl scripting language and the Tk toolkit, a programming environment for creating graphical user interfaces under X Windows together represent one of the most exciting innovations in X Window System programming. Because Tcl and Tk are so easy to learn, extremely powerful, and contain sophisticated features, they have dramatically reduced development time for thousands of X programmers. Written by the creator of Tcl and Tk, this book is the single authoritative resource for anyone who wants to work with this extraordinary environment. The book offers an introduction and overview of Tcl and Tk and then presents detailed instructions for script writing in Tcl and working with the Tk toolkit. You will discover how Tk's windowing shell, wish, enables you to develop window-based applications with amazingly few lines of code. You will also find information on Tk's novel and powerful facility for linking applications. Many other features are also described, such as Tk's hypertext and hypergraphics widgets and Tcl's facilities for procedures, list management, and subprocess execution. For interested readers, the book also describes the C interfaces for Tcl and Tk, showing how to extend their built-in features by writing new C commands. Upon reading this book, you will learn how to produce far more powerful X Windows System applications in a fraction of the time that used to be required.