This document introduces PHP by defining it as a widely-used open source scripting language for web development. It can be embedded into HTML. The document discusses when and why to use PHP, including that it integrates well and has great documentation. It also outlines several ways to learn PHP, such as using frameworks or Quick Web Application Builder. It provides instructions on setting up a development environment and creating a first PHP program and connecting to a database. Overall, the document provides an introduction to and overview of PHP.