1 Ubiquitous Computing: Applications, Challenges and Future Trends Jaydip Sen ABSTRACT We are witnessing the advent and the evolution of a revolutionary computing paradigm that promises to have a profound effect on the way we interact with the computers, devices, physical spaces, and other people. This new paradigm, called ubiquitous computing, envisions a world where embedded processors, comput- ers, sensors, and digital communication technologies are inexpensive commodities that are available everywhere. Ubiquitous computing will surround users with a comfortable and convenient information environment and a smart space that merges physical and computational infrastructures into an integrated habitat. This habitat will feature a proliferation of hundreds or thousands of computing devices and sensors that will provide new functionality, offer special- ized services, and boost productivity and interaction among the devices and the users. This chapter provides a comprehensive discussion on the central trends and the emerging impacts of ubiquitous computing considering them form technical, social and economic perspectives. It also identifies various application areas and sectors that will potentially be benefitted and will be able to provide enhanced and rich experience to the users. The challenges of ubiquitous computing that require active research and technological advancements are also discussed. 1. Introduction The dissemination and use of modern information and communication technologies (ICT) are considered to be the preconditions today for dynamic economic growth and future viability in global competition. At the same