The document defines cloud computing and its key characteristics, service models, and deployment models. It discusses the essential characteristics of cloud computing which include on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. The three main service models are Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). The four deployment models are private cloud, public cloud, hybrid cloud, and community cloud.