This document provides an overview of the key concepts relating to the Internet and intranets. It defines the Internet as a massive global network that connects computer networks around the world. It describes how the Internet works using protocols like TCP/IP and how users can connect. It also differentiates the World Wide Web from the Internet, defining the Web as a system that uses the Internet's transport functions and standards like HTML and HTTP. Finally, it discusses intranets and how they are private networks that use the same Internet protocols within an organization.