Like a number of the reviews, I am of a dual mind on this volume. First it is the best (ok, so it is the ONLY) volume on how to get started using the perl/Tk libraries, and it is highly useful to one who has not done much with Tk. The volume leads one through most of the common widgets which would be useful to create simple GUI applications to replace the common script based interface we all know and love/hate. However, this volume is, by far, the most error filled of any O'Reilly book, with the bulk of the supplied examples not functional as written, and much of the explanation just plain wrong. I was only able to get past certain problems by rereading the "learning" book repeatedly, comparing it to the desktop reference (which is excellent by the way) and studying the pod in the library distribution. All I can say is thank heavens that the library authors aligned with the perl philosophy that things should be highly regular. I own many hundreds of dollars of O'Reilly volumes, and while I am not sorry I bought this book when I did, the disturbing lack of editorial quality will leave me forever cautious about buying another O'Reilly first edition (I mean, once bitten, etc). I would like to add my name to the long list of dissapointed purchasers who want a free upgrade. I would agree wholeheartedly with the opinions that this subject is sufficiently interesting to deserve other volumes discussing some of the more difficult aspects of GUI design and application building. For example, what is the best way to load a file into the text widget? Is there different techniques which are useful for different size files? (The answer is yes.) Why is this so? Uh, however, I'll wait for the third printing... Also, the actual libraries are written with a specific framework in mind, and it would be highly useful to be better able to understand that framework in some detail (I mean, what does "ADVERTISE" *DO*) so one can avoid some of the novice traps.