Ian Douglas is an Associate Program Director at the Learning Systems Institute at Florida State University and an Associate Professor in the university's College of Communications and Information. His research interests focus on improving human performance, particularly through knowledge management and user-centered design of technology. Dr. Douglas has a multidisciplinary background, with an M.A. (hons) in Psychology, an M.S. in Computing and Cognition and a Ph.D. in Computing. He previously worked as a consultant in a flight simulator company and as an educator in the U.K. and Singapore. He has been a visiting professor in the Philippines and China.   At Florida State, Dr. Douglas has been the principal investigator on a number of large research projects funded by the US army, State of Florida and the U.S. Department of Education. His most recent project investigates the role of web-enabled mobile technology in enhancing school field trips to science museums and nature centers. He has also completed several web-based databases with map-based interfaces, including one that was the inspiration behind this book. Zhengjie Liu is the founder and director of Sino European Usability Center (SEUC), professor at School of Information Science & Technology of Dalian Maritime University, China. He is Adjunct Chair for Developing Worlds at ACM SIGCHI, expert member of IFIP TC.13 HCI Committee, co-founder and co-chair at ACM SIGCHI China. His areas include usability, user-centered design and human-computer interaction (HCI). He has been working in usability and HCI since 1989. He founded SEUC in 2000 as a leading research and educational center dedicated to usability/HCI in China. Since then, he has led SEUC conducting many research projects sponsored by leading players in industry including Fortune 500 multinationals and funded by EU and Chinese government.  He is on the editorialboard of the Springer international journal Universal Access in Information Society. He also served as co-chair at international conferences including INTERACT, CSCW etc. He holds an B.E. and an M.E. Degree in Computer Science from Xian Jiaotong University, China.