This document provides an introduction to cloud computing. It defines cloud computing and discusses its key characteristics including elasticity, multi-tenancy, and utility computing. The document outlines the different types of cloud services including Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). It also discusses the technologies that enable cloud computing such as virtualization and containerization. The document uses examples like Amazon Web Services, Google Cloud, and OpenStack to illustrate cloud concepts.