I had high hopes for this book, based on my enthusiasm for John and his other books. I guess I found the insights illuminating at times, and a bit thin or frustrating at others. It's also interesting to note that his examples in various cases might have been different had the iPhone been known of at the time (the interface, underlying complexity, cohesiveness of layers of data etc). I think it's a worthwhile read, and I'll probably go back through again to distill it better (NOT an example of simplicity!), but it's brevity just doesn't allow for a full realization of the concepts.