The Complex Cyber Infrastructure (CCI) group is part of the Informatics Institute at the University of Amsterdam. CCI focuses on the complexity of man-made systems on all scales. Cyber Infrastructure is rapidly evolving from relatively simple fixed components to programmable and virtualized objects with many degrees of freedom, owned, operated and governed by different entities in multiple administrative domains interacting on the Internet. Harnessing this complexity in a transparent, trust-able way for safe and secure data processing is a major research topic that defines the focus of CCI research. The challenges are addressed by combining methods and results from research into distributed data processing, programmable networks, policy reasoning and normative control, hardware and cryptographic security, and software language engineering.