Thomas Ludwig reveals design characteristics when aiming at researching information infrastructures and their diverse information resources, types of users and systems as well as divergent practices. By conducting empirically-based design case studies in the domain of crisis management, the author uncovers methodological and design challenges in understanding new kinds of interconnected information infrastructures from a praxeological perspective. Based on implemented novel ICT tools, he derives design characteristics that focus on integrating objective and subjective queried insights into situated activities of people as well as emphasizing the subjective nature of information quality. Content Researching the Formation of a Public through Modern ICT Examining Individual’s Activities ‘in the Wild’ Assessing and Structuring Citizen-Generated Content in Social Media Aligning Physical and Digital Activities of Citizens Supporting the Research of Information Infrastructures Target Groups Lecturers and students of information systems, computer science, computer-supported cooperative work, human-computer interaction, and science and technology studies Software developer and interaction designer The Author Thomas Ludwig studied Information Systems at the University of Siegen (Germany) and Newcastle (Australia). He finished his PhD in 2016 and is currenlty a senior researcher at the University of Siegen focusing on human-centered ICT design.