"Social Informatics" is a scholarly book that presents the revised contributions from two workshops held during the 5th International Conference on Social Informatics, SocInfo 2013, in Kyoto, Japan. The workshops, which focused on the quality, motivation, and coordination of open collaboration as well as on histoinformatics, provide deep insights into specific areas of social informatics. The 11 selected and carefully reviewed papers come from a wide range of submissions and highlight innovative algorithms and methods for improving quality and motivation in open collaboration. Additionally, the interface between computer science and history is addressed to promote a new research direction in computer-assisted historiography. This book is aimed at professionals and students interested in the developments and challenges in social informatics.