Much has changed since the first edition of human¿computer interaction was published. Ubiquitous computing and rich sensor-filled environments are finding their way out of the laboratory, not just into movies but also into our workplaces and homes. The computer has broken out of its plastic and glass bounds providing us with networked societies where personal computing devices from mobile phones to smart cards fill our pockets and electronic devices surround us at home and work. The web too has grown from a largely academic network into the hub of business and everyday lives. As the distinctions between the physical and the digital, and between work and leisure start to break down, human-computer interaction is also changing radically.