Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A smart device is a device that is digital, active, computer networked, is user reconfigurable and that can operate to some extent autonomously. The term can also refer to a ubiquitous computing device: a device that exhibits some properties of ubiquitous computing including artificial intelligence. Smart devices can be designed to: support a variety of form factors support a range of properties pertaining to ubiquitous computing be used in any combination of three main system environments: physical world, human-centred environments and distributed computing environments.