The objective of the theme “interaction and visualization” is to study how can interactive computer systems empower humans, in particular when they interact with data. This multidisciplinary theme combines different areas of computer science (e.g., human-computer interaction, information visualization, machine learning, signal processing) with a range of disciplines such as cognitive psychology, social psychology, cognitive ergonomics, and art. One of its goals is to better understand how to best mobilize computer hardware and software to support human understanding of complex data, with technologies such as virtual and mixed-reality environments, large displays and telepresence rooms, touch- and gesture-based interfaces, tangible interfaces, affective computing systems, and scalable big data infrastuctures. At a more fundamental level, this theme also seeks to better understand how humans perceive, think, learn, communicate, collaborate, solve problems and make decisions with data. Thus the scope of this theme is both fundamental — e.g., modeling the phenomena occurring when humans consume, process or produce data, or using the tools of Information Theory to model, design and evaluate interactive techniques — and applied, with various contexts and application areas such as scientific discovery, product lifetime management, decision support, education and training, and disability. One key focus is on the use of interaction and visualization to promote the transparency and accountability of algorithms as used in machine learning, robotic systems and intelligent systems. Finally, this theme also studies how can data be used to enhance the interaction between humans and computers more broadly, such as when using new machine learning techniques for supporting gesture-based and full-body interaction.