1. Doxygen is a documentation generator that can generate documentation from comments in source code. It supports multiple programming languages and output formats like HTML, PDF, LaTeX and more. 2. Doxygen works by using special markup comments in source code. A configuration file is used to customize the output. Running Doxygen processes the source code and comments to generate documentation. 3. Automating documentation with Doxygen provides benefits like single sourcing code and docs, automatic updates, less errors, and better organization. It allows maintaining parity between code and documentation.