AUCTeX is an extensible package for writing and formatting TeX files in GNU Emacs and XEmacs. It supports many different TeX macro packages, including AMS-TeX, LaTeX, Texinfo, ConTeXt, and docTeX (dtx files).AUCTeX includes preview-latex which makes LaTeX a tightly integrated component of your editing workflow by visualizing selected source chunks (such as single formulas or graphics) directly as images in the source buffer. Features: - Insert macros, environments and headings with a simple key stroke or via a menu entry. AUCTeX will help you by prompting for parameters in case of known macros and environments. There is a completion mechanism for partially written macros available as well. - Use keyboard shortcuts for inserting math. - Sophisticated fontification and indentation of macros and environments. - Fold macros and environments and display their content or a pre-defined string instead. You can temporarily reveal the original text again for editing.