At first glance, $20 bucks or so may seem a lot for a small 1/4" thick book. I thought so, but I got this reference anyway as I was developing a new college course in passive design. I have become quite impressed with the scope of the material in this little reference. Of course, due to its size, it is not the comprehensive reference on any one topic. However, it is good primer on up-do-date thinking on basic concepts in sustainable design, not just solar issues. For example, it addresses life cycle analysis from the Ecology-Equity-Economy model, not just analyzing the cost-benefits on ROI. I am recommending it to my students to get for a condensed review of our course for their future design and engineering work.