WWW book information: http://www.aw.com/cseng/books/efftcl/
Practical information on how to exploit the full potential of Tcl/Tk.
This is a great second book for someone learning Tcl and Tk. It covers many of the topics that someone wanting to develop excellent skills as a Tcl programmer will want to learn.
Or maybe even first; in the comp.lang.tcl newsgroup, SH writes, "Effective Tcl/Tk is an outstanding book, if you're looking into the Tk portion more. I'm a newbie myself, and still reading the book. It's very clear, full of tips & tricks for newbies, and surprisingly concise."