Digital Painting Techniques is exactly what I'd hoped it would be, a book packed with practical and genuinely useful tips and tricks on how to paint in a natural media style within Photoshop.
It's densely illustrated in colour throughout with various artists demonstrating their preferred techniques. The layout and presentation is more like a magazine than reference book with shortish, easy to follow articles, showing not just how to create a brush [for example], but why you would want to do so and how it's used within the image. It's certainly not a rigid rule book and is more like someone informally passing on handy tips, rather than standing over your shoulder instructing you to do it the 'correct' way.
Although the book is generally laid out in a step-by-step format, it is not a how to use Photoshop (or how to paint) book. As such complete novices are likely to find this book goes over their heads. In fairness the assumption that the reader is already pretty familiar with Photoshop and drawing tablets is useful, as it means the book gets straight to the heart of the subject, rather than wasting half the book explaining menus and the like. Besides, if you're after a "How to use Photoshop" book there are plenty of books already available that will get you started, before moving onto this.
My only minor criticism would be that the some of the reference images are occasionally laid out in an counter intuitive sequence, other than that this is a excellent book on practical digital painting and is worth every penny.