The explosive growth of the Internet and the distributed systems that build upon it are exposing the limits in our understanding of how to build networked systems, what the underlying network looks like, how people interact in these environments, and even the research model we should apply to explore these issues. My work is motivated by these challenges. I am particularly interested in the measurement, analysis and design of Internet-scale. Much of my work focuses on improving the visibility of measurement of networked systems and leveraging this visibility to characterize distributed systems, networks and their interactions, and design new and improved systems based on the gained insight.