Digital information awareness is the process by which people obtain knowledge about important personal information stored on their computers. This is usually provided graphically: when information is hidden from view it must be summoned to the front and users are interrupted by the system, disregarding the costs of the interruption. A solution is to use speech output to complement the graphics, but its use invokes anthropomorphic feelings whose cues must be carefully controlled if the system is to be regarded as humanized. This book describes the design of a speech-based assistant nased on a set of intelligent agents and demonstrates how the content contextually cues the significance of visually hidden information, and how the delivery impacts on the social acceptability of a speaking system, including attentive interruptions, linguistic variation and politeness. An empirical study showed that people felt a degree of rapport with the such a system. These results led to the abstraction of design guidelines for speech-based systems that purport to be humanized in nature. The book is useful to scholars and professionals concerned with the design of next-generation user interfaces.