Cloud computing can and does mean different things to different people. The common characteristics most interpretations share are on-demand scalability of highly available and reliable pooled computing resources, secure access to metered services from nearly anywhere, and displacement of data and services from inside to outside the organisation. While aspects of these characteristics have been realised to a certain extent, cloud computing remains a work in progress. This book provides an overview of the security and privacy challenges pertinent to public cloud computing and points out considerations organisations should take when outsourcing data, applications, and infrastructure to a public cloud environment.