LaTeX is a software system for document preparation used for the communication and publication of scientific documents in many fields, including mathematics, computer science, engineering, physics, chemistry, economics, linguistics, quantitative psychology, philosophy, and political science. It is a high-quality typesetting system that includes features designed for the production of technical and scientific documentation. LaTeX uses plain text as opposed to the formatted text found in WYSIWYG word processors like Microsoft Word, LibreOffice Writer, and Apple Pages. It is not a word processor, but rather a document preparation system that encourages authors to concentrate on getting the right content and leave document design to document designers. LaTeX is based on the idea that it is better to let authors get on with writing documents while TeX handles the layout side, and LaTeX handles the content side. LaTeX is free software and is distributed under the LaTeX Project Public License. It can be used as a standalone document preparation system or as an intermediate format. LaTeX is written in the TeX macro language and uses the TeX typesetting program for formatting its output.