[caption id="attachment_27921" align="alignleft" width="150" caption="Online learning has the power to transform education, as the creation of free online universities demonstrates."][/caption]

Although technically it was published in 2008, Disrupting Class: How Disruptive Innovation Will Change the Way the World Learns, by Clayton Christensen, Curtis W. Johnson, and Michael Horn, made a huge impression in the past year, and its authors spoke at numerous education conferences in 2009. Their ideas proved quite prophetic later in the year, when a new