This book has clear directions, full page illustrations of most of the dishes, smaller illustrations of several individual steps of most recipes, and an impressive array of your favorite Indian dishes. There's a guide to common ingredients in Indian food. So on all of those fronts, it's great.
The reason it gets a 4 instead of a 5 is that we've had mixed results with the actual recipes. We made the chicken korma, and it came out runny and lumpy and very weird. This was a big disappointment, and it caused us to mistrust the book. However, tonight we made the chicken tikka masala, and it was delicious.