LyX is an "open source" word processor. That is, the source code for the program is freely available. It may be one of the relatively few open source projects available for general users (open source projects tend to be for technical users, such a Linux). LyX bills itself as a "WYSIWYM" -- What you See is What You Mean word processor. While it has a graphic interface, it uses LaTeX, and consistent with LaTeX, it "encourages an approach to writing based on the structure of your documents, not their appearance. LyX lets you concentrate on writing, leaving details of visual layout to the software." It is particularly strong on formatting technical documents (including mathematical terms). LyX is also a useful choice for those who want to generate LaTeX output but don't want to learn LaTeX. Freely available versions are available for many platforms (most versions of Unix and Windows).