This book is not written from the standpoint it claims. It is not always clear what the authors are referring to. The code examples are poorly defined. In the front of the book, they say they’ll use bold text to highlight important changes in code examples; this is never used.They also wrote from a point of view that understands what they are talking about; glad they get it, they certainly failed to pass on that understanding. If you have no clue about ExtJS, you will have no clue what they’re talking about. I’ve had to read some sections 5 times to connect the dots. I never read things more than twice to understand them, so this is most annoying.Throughout the book, they will “add code” to a previous file, but with no indicator where in the file the additions should go. Even worse, the naming conventions used make it very confusing as to which file they’re talking about.Overall, a very disappointing purchase. I would not recommend. It’s not a handy reference, it doesn’t teach. It just regurgitates. Which is great for the authors. Glad they know wtf they’re talking about. Major fail passing that knowledge along.