Assuming that you recognise that you should be adding scripting tools to your skill set, the question that may arise is which ones and where to start. This book will not directly answer that question nor will it teach you to use any scripting language. What it will do is give you a general feel for the subject coupled with reasonably detailed understanding of the (dis)advantages of a range of possible choices. The book is not comprehensive in its coverage. For example, it does not even mention Delphi or Python.
If you are not yet ready to choose which scripting language to learn first, reading this book may help refine your ideas and understanding before you dive in and study a scripting language.
Now the author might argue that he has tried to do something more by actually tackling such topics as advanced use of Tcl. However, I would not try to learn any language from this book. I would look for a book dedicated to the language. As I have said, the value of this book is in helping you grasp the range of choice available to you. I think this book is worth reading but it is probably not worth investing study time on it.