Book excerpt: In just a few chapters you will learn about Tcl features that allow you to isolate and protect your code from being damaged in large applications. You will even learn how to extend the language itself. Tcl/Tk: A Developer's Guide clearly discusses development tools, proven techniques, and existing extensions. It shows how to use Tcl/Tk effectively and provides many code examples. This fully revised new edition is the complete resource for computer professionals, from systems administrators to programmers. It covers versions 7.4 to 8.4 and includes a CD-ROM containing the interpreters, libraries, and tutorials to get you started quickly. Additional materials in the book include case studies and discussions of techniques for the advanced user. On the CD-ROM *Distributions for Tcl 8.3 and 8.4 for Linux, Solaris, Macintosh, and Windows. *A copy of ActiveTcl from ActiveState. *The latest release of TclTutor. *How-to's and tutorials as well as copies of all the tools discussed in the book.