<p>The proliferation of Internet access has enabled the rapid and widespread exchange of information globally. The world wide web has become the primary communications platform for many people and has surpassed other traditional media outlets in terms of reach and influence. However, many nation-states impose various levels of censorship on their citizens' Internet communications. There is little consensus about what constitutes “objectionable” online content deserving of censorship. Some people consider the censor activities occurring in many nations to be violations of international human rights (e.g., the rights to freedom of expression and assembly). This multi-study dissertation explores Internet censorship methods and systems. By using combinations of quantitative, qualitative, and systematic literature review methods, this thesis provides an interdisciplinary view of the domain of Internet censorship. The author presents a reference model for Internet censorship technologies: an abstraction to facilitate a conceptual understanding of the ways in which Internet censorship occurs from a system design perspective. The author then characterizes the technical threats to Internet communications, producing a comprehensive taxonomy of Internet censorship methods as a result. Finally, this work provides a novel research framework for revealing how nation-state censors operate based on a globally representative sample. Of the 70 nations analyzed, 62 used at least one Internet censorship method against their citizens. The results reveal worldwide trends in Internet censorship based on historical evidence and Internet measurement data. </p>