this document gives you an orientation on "z.m.l.", short for "zen markup language".
z.m.l. is a light-markup format, similar to restructured-text, textile, asciidoc, and the one most-widely-used currently, markdown.
z.m.l. was designed explicitly for "long-form" documents, such as books, journal articles, user-manuals, and similar types of material.
perhaps the best defining characteristic of "long-form" documents is that they typically consist of several sections, and thus require a table of contents. if your document is one that would benefit from a table of contents, you'll probably find it wise to use z.m.l. for it, because z.m.l. has the features you will need.