I've read other books written by the authors of the language, and found them to be lacking. But this author's book is really well organized, thoughtful, clear, and has great explanations. I was up and running creating widgets, etc. in a matter of no time.I think this book is more of an instructional guide (and a damn good one too), but I don't believe it is oriented as a reference guide. I know that there were a few gripes on this should be both, but I wouldn't want that. Technology changes, so I prefer references to remain online. Gone are the days to cart a wheel-barrel of reference material for a given project, only to be obsoleted in a few years.This book opened the doors to the great wonderful world of Tcl/Tk. And I am confident it will help others in years to come.