Welch has written a tutorial on the Tcl scripting language and the Tk toolkit for X Windows. Although the book discusses both Tcl and Tk, its emphasis is on the latter. The first nine chapters discuss the use of Tcl scripts to write programs. They cover language constructs, procedures, debugging, and the use of script libraries. The next 19 chapters deal with Tk. Beginning with a simple example program in Tk that draws a window, the author proceeds to describe various aspects of writing graphical user interfaces using Tk. The book exhaustively covers issues such as buttons, handling input events, and the myriad widgets that are provided. Readers who have seen books on Windows or X programming will find this treatment familiar. The last part of the book discusses other topics, such as the use of Tcl and Tk with the C language, surveys of Tcl extensions, and porting issues to Tk 4.0.

I find it easiest to characterize this book by comparison with Ousterhout’s original book Tcl and the Tk toolkit [1]. Welch’s book was written later, after the user community had more experience with the languages. It shifts the focus from using Tcl and Tk in conjunction with C to their standalone use in building complete applications. Unlike  Ousterhout’s  book, this book includes lots of recommendations on the style that should be followed in building applications as well as examples that can be incorporated into user applications. (The book comes with a diskette containing all the examples.) I found the examples clear and topical. The hints and advice sprinkled throughout the book are also helpful in pointing out gotchas. All this combines to make this an excellent book to read if you are interested in building Tcl and especially Tk applications. The weaknesses of this book are the converse of its strengths. If you are interested in a reference book and in integrating Tcl and Tk with C programs, then Ousterhout’s book would be more appropriate.