David Wolfe’s Superfoods is an okay book, at best a one-time read. The thing that got my goat with David’s book is that foods that have less commercial value are relegated into the background. For instance, chlorella, spirulina, coconut oil, nutritional yeast can also be considered as a superfood. The focus is on cacao and maca since these have more commercial value.
If you want unbiased information about superfoods, then please read Susan Smith Jones’ work on the same subject.