Remarkable. "Today the National Academies Press announced it would offer its entire PDF catalog of books for free, as files that can be downloaded by anyone.... Barbara Kline Pope, executive director for the press, said it had previously offered 65 percent of its titles-ones that were narrow in scope-for free. 'The 35 percent that we are adding today will reach a wider audience, and we are doing it because it's central to our mission to get this information to everyone,' she said." The system asked me for my email address before allowing me to download the PDF, but I could read the HTML on the website without paying anything. I figured the email address was a good thing to exchange for a free copy of Learning Science Through Computer Games and Simulations, which I have open in my PDF reader right now.