This document provides an overview of cloud computing. It defines cloud computing as using computing resources over the Internet rather than owning local hardware and software. The key benefits are lower costs through economies of scale and flexibility to scale resources up or down as needed. There are three main delivery models: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). IaaS provides basic storage and computing resources, PaaS provides development environments, and SaaS provides complete applications. Cloud services can be public, private, or hybrid combinations of both.