Cloud computing, an emerging form of computing where users have access to scalable, on-demand capabilities that are provided through Internet-based technologies, has the potential to provide information technology services more quickly and at a lower cost, but also to introduce information security risks. Cloud computing can both increase and decrease the security of information systems in federal agencies. Potential information security benefits include those related to the use of virtualisation, such as faster deployment of patches, and from economies of scale, such as potentially reduced costs for disaster recovery. Risks include dependence on the security practices and assurances of a vendor, dependency on the vendor, and concerns related to sharing of computing resources. This book provides an overview of the background, benefits, and risks of cloud computing and government usage.