David Green is Professor of Information Technology at Monash University. His research concerns complex systems, both the underlying theory and its impact on real-world problems. In the course of his research into complexity he has investigated problems as diverse as forest ecology, evolution, proteins, geographic information and social networks. His many articles and publications include several books directed at a general audience, including The Serendipity Machine (2004), and Patterns in the Sand (1998). His most recent book, Of Ants and Men (2014), deals with unexpected events, why they happen, how they cascade to cause accidents and disasters, and how they impact on society.