  The study of network robustness is a critical tool in the characterization
and sense making of complex interconnected systems such as infrastructure,
communication and social networks. While significant research has been
conducted in all of these areas, gaps in the surveying literature still exist.
Answers to key questions are currently scattered across multiple scientific
fields and numerous papers. In this survey, we distill key findings across
numerous domains and provide researchers crucial access to important
information by--(1) summarizing and comparing recent and classical graph
robustness measures; (2) exploring which robustness measures are most
applicable to different categories of networks (e.g., social, infrastructure;
(3) reviewing common network attack strategies, and summarizing which attacks
are most effective across different network topologies; and (4) extensive
discussion on selecting defense techniques to mitigate attacks across a variety
of networks. This survey guides researchers and practitioners in navigating the
expansive field of network robustness, while summarizing answers to key
questions. We conclude by highlighting current research directions and open
problems.
