We propose an AmbientBrowser system that helps people acquire knowledge during everyday activities. It continuously searches Web pages using both system-defined and user-defined keywords, and displays summarized text obtained from pages found by searches. The system’s sensors detect users’ and environmental conditions and control the system’s behavior such as knowledge selection or a style of presentation. Thus, the user can encounter a wide variety of knowledge without active operations. A pilot study showed that peripherally displayed knowledge could be read and could engage a user’s interest. We implemented the system using a random information retrieval mechanism, an automatic kinetic typography composer, and easy methods of interaction using sensors.