From the title of the book it could be expected a share of both topics, wind and solar energy, however the book is full of wind power analysis everywhere,concentrating solar power is almost non existing, just a couple of pages on chapter 17, and considering the number of applications and complexity of this topics it deserves a lot more than that. So the book is nice but one should not expect too much of anything but wind energy, which is fine. On photovoltaic there is not much either, including nothing on emerging technologies in the field, so it is fairly classic what you have there for conventional design but not giving any clue of what comes next. For instance flexible systems for non flat roof applications or any other non regular shape buildings or semi transparent components. When considering grid connections it goes again for wind almost inmediately. This is fine but my point is whay do not call the book "wind power with some solar..." instead of giving the wrong impression ?, so I give 4 starts for wind and 2 for solar (really it should be just one) giving 3 as average.