Clayton Lewis is a Professor of Computer Science and Fellow of the Institute of Cognitive Science, at the University of Colorado, Boulder, where he has been based since 1984. He is well known for his research on evaluation methods in user interface design. Two methods to which he and his colleagues have contributed- the thinking aloud method and the cognitive walkthrough- are in regular use in software development organizations around the world. He has also contributed to cognitive assistive technology, to programming language design, to educational technology, and to cognitive theory in causal attribution and learning. He was named University of Colorado President's Teaching Scholar in 1989, a life title signifying the University's highest award for teaching. In Spring 2017 he was a fellow at the Hanse Wissenschaftskolleg in Delmenhort, Germany. Lewis earned an AB in mathematics from Princeton University, an MS from MIT, for interdisciplinary study in mathematics and linguistics, and a Ph.D.

from the University of Michigan in experimental psychology. He was elected to the ACM CHI Academy in 2009, recognizing his contributions to the field of human-computer interaction. In 2011, he was further recognized by the ACM CHI Social Impact Award for his work on technology for people with cognitive, language, and learning disabilities. John M. Carroll is Distinguished Professor of Information Sciences and Technology at Penn State University, and was a founder of human-computer interaction. He served on the program committee of the 1982 Bureau of Standards Conference on the Human Factors of Computing Systems that in effect inaugurated the field and was the direct predecessor of the field's flagship conference series, the ACM CHI Conferences. Through the past two decades, Carroll has been a leader in the development of the field of Human-Computer Interaction. In 1984 he founded the User Interface Institute at the IBM Thomas J.

Watson Research Center, the most influential corporate research laboratory during the latter 1980s. In 1994, he joined Virginia Tech as Department Head of Computer Science where in 1995 he led the effort to form the university's Center for Human-Computer Interaction. That year, Virginia Tech was invited to join the Human-Computer Interaction Consortium, a group of the leading corporate and academic HCI research organizations in the world. He has written more than 250 technical papers, more than 25 conference plenary addresses, and 13 books, including HCI Models, Theories, and Frameworks, and Usability Engineering (with Mary Beth Rosson). He serves on 10 editorial boards for journals and handbooks, and is the current editor-in-chief of ACM Transactions on Computer- Human Interaction (ToCHI). He has won the Rigo Career Achievement Award from ACM (SIGDOC), received the Silver Core Award from IFIP, and is a member of the CHI Academy. In 2003 he became the fifth recipient of the CHI Lifetime Achievement Award, the most prestigious research award in HCI.