Abstract: An increasing number of devices (e.g., household appliances, PDAs, cell phones) have microprocessors and will soon be able to exhibit sophisticated behaviors and interactions with other devices: a home heating system will monitor its residents' alarm clocks and schedules to set the temperature optimally; a car's GPS system will use local traffic reports to optimize its driver's route based on road conditions. The Sagres project at the University of Washington addresses the key issues of data sharing and management in the realm of invisible computing.