Ubiquitous computing (UBICOMP) is a term used for human interaction with computers in virtually everything we do and almost everywhere we go. It is embedding computers in our daily lives to create an active and intelligent environment [1]. This is future phase of computers, which is beyond the desktop and notebook environment, where we are currently in and we are progressively heading deeper inside this new phase. In Ubiquitous Computing we mainly focus on computer being integral part of human such that we are unaware of their presence. Computer scientists are focusing hard on ways how the interaction between human and computer can be simplified. We can think of an era where we are surrounded with over hundreds of computers each doing a unique task irrespective of location and time and keeping human unaware. In this article we explore about the evolution of ubiquitous computing from its origin and history, its architecture, role of privacy and integration of privacy in system design, its Features and Technical Challenges. Ubiquitous computing is the third wave in computing, which has begun just now. Ubicomp is a field where we require considerable efforts to match up the current technological developments. According to the view of Computer Scientists and Engineers in future we will be having such a technological advancement in this field that will amaze the world.