Abstract. The move from traditional desktop computing environment to ubiquitous and mobile computing have brought to the front Context-aware applications which are capable of providing appropriate information and services to the user depending upon the computational/user context. This paper attempts to discuss the concept of Context-awareness from functionality perspective. The components and characteristics of Context-aware systems are identified and described in terms of the requirements expected from other applications. The different architectural approaches used in the envisioning of context-aware systems are presented to highlight the functionalities and quality concerns which dictate their choice. Moreover, Context-aware frameworks and middleware which facilitate the efficient development of Context-aware applications are highlighted as instantiations of various architectural styles. Finally, the paper highlights the importance of context-awareness for pervasive computing by discussing sample applications in diverse fields of education, health and tourism.