I am president and chief developer for Runestone Academy a non-profit company I founded. The mission of Runestone is to "democratize textbooks for the 21st century". To accomplish that mission we make high quality interactive textbooks available for free to all students. In the 21st century it is silly to ignore the wonderful possibilities for interactivity in a web browser, so we make great interactive textbooks that engage students in learning. It would also be silly to ignore the rich