LyX is a free and open Document Processor for Linux, Windows and MacOS. Using LyX write scientific documents, thesis, books and mathematical content easily with its build-in powerful formula editor. It is using WYSIWYM writing structure of your documents. It comes with Tex and Latex support and you can also create a simple letter or a novel or a theater play or film script using this application. it is released under the GNU General Public License, version 2 or later.