This work serves as a thorough, yet simple-to-read, reference on various aspects of cloud computing security. The text opens with an introduction to the general concepts of cloud computing necessary to build a basic understanding of the cloud, followed by a discussion of aspects of security. The work then examines how cloud security differs from conventional information security, and reviews cloud-specific classes of threats and attacks. A range of varying threats in cloud computing are covered, from threats of data loss and data breaches, to threats to availability and threats posed by malicious insiders. The text discusses cloud security attacks on different levels, including attacks on the hypervisor, and on the confidentiality of data. Newer attacks, such as side-channel attacks and resource-freeing attacks, are also described. The work concludes with a set of general security recommendations for the cloud.