Authors: Brent Welch, Jeff Hobbs, Ken Jones
This book is now available.
This book is up-to-date with Tcl/Tk 8.4.
The book's home page is http://www.beedub.com/book/
There are about 20 sample chapters available at [L1 ] taken from the 4 editions. They cover topics from the basic Tcl and Tk introductions, through more advanced topics like Regular Expressions, Eval, Socket programming, Thread programming, TclHttpd, and Starkits.