Cloud computing is a new technique in the history of services which are offered in the internet. It has completely changed the way of use of the power of computers irrespective of any geographic location. The biggest profit for organizations and businesses is that it offers services using hardware, software and platform of third party sources. It is very economical as it saves cost and maintenance. Cloud computing comes in several different forms. To minimize the cost and avoid duplication of resources, infrastructure like software, hardware and manpower are used . Emerging technologies like server virtualization and cloud computing in libraries are increased. In this paper, a schedule has been made to give an overview of how service, platform and infrastructure forms of cloud computing has been used to serve the library needs. This paper discusses about the characteristics, types, advantages and disadvantages, role of cloud librarian, use of technology and initiatives of cloud computing. This attempt has also been made to overview the areas in libraries where these technology can be deployed to provide better library services and the productivity of library staff can be augmented or not.