The on-demand availability of computer system resources without direct active management by the user is known as cloud computing. It is usually used to refer to the data centers, which are available over the Internet to many users. A few major types of clouds are enterprise clouds, public clouds and hybrid cloud. Enterprise clouds, also called private clouds, are usually limited to a single organization while public clouds are available to many organizations. A hybrid cloud is a cloud computing service, which is made up of a fusion of public, private and community cloud services. Cloud computing majorly relies on sharing of resources to achieve economies of scale and coherence. Cloud computing is an upcoming field of science that has undergone rapid development over the past few decades. Different approaches, concepts and technologies related to this field have been included in this book. It will serve as a reference to a broad spectrum of readers.