This book looks at open data practices historically and from the perspective of those currently involved in advocating for making government data freely available. Based on interviews with practitioners, users and evangelists across three Australian-based case studies illustrating contemporary open data practices, this book discusses how open data has evolved, why certain barriers to openness exist and what the future of open data might look like. It highlights both the challenges and approaches to ‘best practice’ in government departments and agencies as they adapt to changing data ecosystems and public expectations around access, transparency, risk and responsible stewardship.