From their website...
"For more than 140 years, the NAS, NAE, IOM, and NRC have been advising the nation on issues of science, technology, and medicine. Like no other collection of organizations, the Academies enlist the nation’s foremost scientists, engineers, health professionals, and other experts to address the scientific and technical aspects of society’s most pressing problems. The results of their work are authoritative and independent studies published by the National Academies Press.
NAP produces more than 200 books a year on a wide range of topics in science, engineering, and health, capturing the best-informed views on important issues."
One of their most popular books, America's Climate Choice, is included. (Look for the "Download Free PDF" button.
Note: if you have an iPad, when you open the book (PDF) in your iPad, you will be given the option download these books directly into iBooks. If you choose this option, the book will appear in your iBooks bookshelf and you will have access to it at any time. (Even when you are offline! Great option for reading when traveling. I catch up with these type of readings while I am on a plane ... I can only do so many Sudokus!)
You can browse all the topics in their entire library at National Academies Press.
