Human-Computer Interaction (HCI; original name: manmachine interaction) is a term known since more than 30 years.The aim of HCI research is to intelligently assist users in improving the interaction with computers (in the sense that this interaction should become more user-friendly and better tailored to the needs and abilities of the users and the capabilities of the involved devices).HCI has its roots in other disciplines, especially in ergonomics and human factors.It is a multi-disciplinary research field, populated by researchers and practitioners from areas like psychology, cognitive science, ergonomics, sociology, computer science, graphic design, business, and more.This special issue on HCI reflects some of the main roads of current research in HCI.It represents a nice multifaceted mix of world-renowned experts from many different disciplines.A good starting point for reading is the very first article of this special issue, "Human-Computer Interaction-