This document provides an overview of Phing, an open source build tool based on Apache Ant. Phing allows users to automate tasks like configuration, packaging, deployment, testing and more through PHP scripts. It is cross-platform and supports features like running tasks in parallel, filtering files, transforming data and extending functionality through custom tasks and extensions. The document demonstrates how to write Phing build scripts and utilize core tasks and functionality like file selection, property handling, conditionals and more.