Short book but unlike a lot of the larger publications, the information is to the point and very useful. Our Center of Excellence team are in the process of planning a workshop for our testers and Greg's book will be one of the hubs that the course will revolve around. If you are serious about automation in an agile world - you HAVE to read this book.
We even used Greg's phrase "what is eating your lunch" as a conversation starter and foot in the door when talking to our Agile Teams.
When asked about recommended books for our new testers - this is one of the top four I recommend.