LyX is a fully featured document processor similar to MS word but freely available under GPL-2(+later) license, it is cross-platform and available for Linux, Windows, Mac, OS/2, and Haiku. It encourages an approach to writing based on the structure of your documents (WYSIWYM) and not simply their appearance (WYSIWYG). It combines the flexibility and power of TeX/LaTeX with easy to use GUI. This results in world-class support for creation of mathematical content (via a fully integrated equation editor) and structured documents like academic articles, theses, and books.
