present). This year, the community meets for the 20 th time to discuss and debate technical, social, and organizational features of collaboration and cooperation. What began with a focus on the office context evolved with the appearance of lower-cost, versatile networked systems to understand how groups work in a variety of contexts and conditions. Today, the Group conference series is a premier venue for research on Computer-Supported Cooperative Work, Human-Computer Interaction, Computer-Supported Collaborative Learning and Socio-Technical Studies. The conference integrates work in social science, computer science, engineering, design, values, and other diverse topics related to group work, broadly conceptualized. Group 2018 continues the tradition of being truly international and interdisciplinary in both organizational structure as well as participants. Our diversity is reflected in the broad methodological and topical coverage of submissions to our program of research papers, working papers, design fictions, posters and demos, workshops, and the doctoral colloquium. 22 out of 94 submissions were accepted to the peer-reviewed papers track and Group 2018 also includes presentation of 4 design fictions, 4 working papers, 16 posters, 2 demos, 3 workshops, and 5 works by doctoral colloquium participants. In addition, GROUP 2018 continues with the initiative of providing authors of recent publications in 'The Journal of CSCW' (JCSCW) the opportunity to present their paper to the community; 3 JCSCW papers have been selected this year. Every year, the Group conference is a collaborative effort among volunteers from around the globe. We thank each of the steering committee, chairs, organizers, reviewers, and submitters, all of whom helped make the 2018 conference an intellectually innovative and community-oriented event where ideas can grow.