This document provides an overview of cloud computing. It begins with prerequisites and an introduction defining cloud computing and discussing its history and similarities to other technologies like client-server models. It then covers the advantages of adapting to cloud including agility, cost savings, reliability, and scalability. Different deployment models like public, private, and hybrid clouds are described along with service models including infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). Technologies for creating and accessing clouds are outlined. Major cloud providers like Amazon, Microsoft, Google, and IBM are listed. The document concludes with criticisms of cloud computing and its future.