This book constitutes the proceedings of the 28th International Symposium on Graph Drawing and Network Visualization, GD 2021, which was held in Tubingen, Germany, during September 14-17, 2021.The 23 full papers and 5 short papers presented in these proceedings were carefully reviewed and selected from 74 submissions. The abstracts of 13 posters presented at the conference can be found in the back matter of the volume. The contributions were organized in topical sections as follows: Best Paper (Track 1: Combinatorial and Algorithmic Aspects); Best Paper (Track 2: Experimental, Applied, and Network Visualization Aspects); Crossing Minimization and Beyond-Planarity; Morphing and Graph Abstraction; Geometric Constraints; Topological and Upward Drawings; Linear Layouts; Contact and Visibility Representations; Geometric Aspects in Graph Drawing; AI applications; and Graph Drawing Contest Report.

As the outcome of the Dagstuhl Seminar 15481 on Crowdsourcing and Human-Centered Experiments, this book is a primer for computer science researchers who intend to use crowdsourcing technology for human centered experiments. The focus of this Dagstuhl seminar, held in Dagstuhl Castle in November 2015, was to discuss experiences and methodological considerations when using crowdsourcing platforms to run human-centered experiments to test the effectiveness of visual representations. The inspiring Dagstuhl atmosphere fostered discussions and brought together researchers from different research directions. The papers provide information on crowdsourcing technology and experimental methodologies, comparisons between crowdsourcing and lab experiments, the use of crowdsourcing for visualisation, psychology, QoE and HCI empirical studies, and finally the nature of crowdworkers and their work, their motivation and demographic background, as well as the relationships among people forming the crowdsourcing community.

Experiments that require the use of human participants are time consuming and costly: it is important to get the process right the first time. Planning and preparation are key to success. This practical book takes the human-computer interaction researcher through the complete experimental process, from identifying a research question to designing and conducting an experiment, and then to analyzing and reporting the results. The advice offered in this book draws on the author's twenty years of experience running experiments. In describing general concepts of experimental design and analysis she refers to numerous worked examples that address the very real practicalities and problems of conducting an experiment, such as managing participants, getting ethical approval, preempting criticism, choosing a statistical method, and dealing with unexpected events.