„Open Government Data“ is about the principles behind the open government data movement and its development in the US. The movement is framed as the application of Big Data to civics, where Big Data is not just the size of data but the ability for data to change the way we understand its subject. Topics include principles of open government data, the history of the movement, applications to transparency and civic engagement, a brief legal history, data quality, civic hacking, and paradoxes in transparency.