This book is useful for anyone with no prior knowledge of or exposure to renewable energy. If you have a basic knowledge of solar and/or wind, particularly residential scale, then this book will probably not be terribly helpful. Its written very colloquially with pithy parables involving dogs and cats. As hokey as I found them, they were effective in demonstrating the author's points. As noted, a useful introductory book but look elsewhere if you need something more advanced covering things like purchase, installation, operation, disconnect, etc.