The John D. and Catherine T. MacArthur Foundation Series on Digital Media and Learning examines the effect of digital media tools on how people learn, network, communicate, and play, and how growing up with these tools may affect a person's sense of self, how they express themselves, and their ability to learn, exercise judgment, and think systematically. The full text of each volume in the Series is provided for free and open access thanks to the generous support of the MacArthur Foundation.