Rating: 

several times to understand everything fully.

This is what I dislike about the book:

1. Occasionally it will refer you towards standards documents for more

   
   information on an interface, but not mention where this can be found.

   
   

2. It uses an imaginary OCR application with made-up interfaces for all its examples.

   
   I feel it would make things easier to relate to the real world if it used

   
   real world interfaces (say, showing how to automate and be automated, perhaps).

   
   

Overall, I feel it is worth the money I paid for it, even though it is not

as easy to follow as other O'Reilly books I have read.