In short, if you want a tactical book on unit testing that distills the passion and love of an expert practitioner into a very readable yet reference-friendly text on unit testing, this is it.
If you are new to unit testing or TDD, this book will demystify the practices, tools and techniques that would otherwise take years and lots of frustration to get right.
If you are an experienced practitioner of unit testing and TDD, and are already practicing SOLID, TOOD, and BDD not just as a flavor of the week but as a way of life, this book will provide unambiguous insight into different approaches that will help you refine your existing techniques or at a minimum, validate your approach which is always valuable to any developer who has an opportunity to review his/her techniques with a seasoned master. This book will afford you that opportunity.
While the book cites excellent references for TDD and design patterns, if there is one thing that I thought was missing was a narrative- even if by way of an appendix- that ties all of the techniques covered together in an example of building the example Logger component using TDD. I understand that this book is not about TDD per se, but at the same time, that's like a book on scuba equipment that teaches you precisely how to pressurize your CO2 tank, keep your mask from fogging up and care and maintenance of your scuba suit not being about scuba diving.
That said, knowing Roy, it must have been painful to resist a detailed examination on TDD, but, for this book to be effective, it had to be relatively short, to the point and most of all pragmatic for it to succeed at filling the void on the topic of unit testing techniques and practices. To that end, Roy hits the mark very elegantly without being pretentious, catering to those who test first, test last or don't (yet) test at all. While I would love for everyone to pick this book up and start doing TDD today, even if you aren't yet convinced on TDD, applying these techniques to writing code that is testable, and learning how to test the right things will be an instant asset to your product, your team and your organization.
You can find the book on Amazon.com: http://www.amazon.com/gp/product/1933988274