Frank E. Ritter is a professor in the College of Information Sciences and Technology, professor in the Department of Psychology, and professor in the Department of Computer Science and Engineering at The Pennsylvania State University.  He has published more than 100 articles and conference papers, and edited several books in the area of cognitive modeling, cognitive architectures, human-computer interaction, and learning. He is on the editorial board of Proceedings of the Human Factors and Ergonomics Society and Artificial Intelligence and the Simulation of Behaviour Quarterly. Gordon D. Baxter is a research fellow in the School of Computer Science at the University of St. Andrews. His background is in human factors and software engineering, with extensive experience in both. His research interests lie in trying to improve the way that systems are developed, and is interested in understanding how decisions and actions taken at all levels (regulatory, organisational, team and individual) affect what happens at the sharp end of the system where the user interacts with the technology His work is influenced by ideas from Resilience Engineering, and Cognitive Systems Engineering which means thinking more functionally about systems as a whole (i.e. people, technology and organisations) rather than taking an atomistic decomposition (or reductionist) type of approach, and focusing on successes as well as failures as a source of learning opportunities. Elizabeth F. Churchill is the Director of Human Computer Interaction at eBay Research Labs in San Jose, California, and is the Vice President of the Association of Computing Machinery's Special Interest Group on Human Computer Interaction (ACM SigCHI). She is an ACM Distinguished Scientist, and writes a column for ACM interactions magazine. She is a Distinguished Visiting Scholar at Stanford University's Media X, the industry affiliate program to Stanford's H-STAR Institute. Previously shehas worked at Yahoo! Research, PARC, and Fuji Xerox's research lab in Palo Alto, FXPAL.