# AsciiDoc

Since version `2.0.0`, GitBook can also accept AsciiDoc as an input format.

Please refer to the [AsciiDoc Syntax Quick Reference](http://asciidoctor.org/docs/asciidoc-syntax-quick-reference/) for more informations about the format.

Just like for markdown, GitBook is using some special files to extract structures: `README.adoc`, `SUMMARY.adoc`, `LANGS.adoc` and `GLOSSARY.adoc`.

### README.adoc

This is the main entry of your book: the introduction. This file is **non optional**.

### SUMMARY.adoc

This file defines the list of chapters and subchapters. Just like [for markdown](./pages.md), the `SUMMARY.adoc`'s format is simply a list of links, the name of the link is used as the chapter's name, and the target is a path to that chapter's file.

Subchapters are defined simply by adding a nested list to a parent chapter.

```asciidoc
= Summary

. link:chapter-1/README.adoc[Chapter 1]
.. link:chapter-1/ARTICLE1.adoc[Article 1]
.. link:chapter-1/ARTICLE2.adoc[Article 2]
... link:chapter-1/ARTICLE-1-2-1.adoc[Article 1.2.1]
. link:chapter-2/README.adoc[Chapter 2]
. link:chapter-3/README.adoc[Chapter 3]
. link:chapter-4/README.adoc[Chapter 4]
.. Unfinished article
. Unfinished Chapter
```

### LANGS.adoc

For [Multi-Languages](./languages.md) books, this file is used to define the different supported languages and translations.

This file is following the same syntax as the `SUMMARY.adoc`:

```asciidoc
= Languages

. link:en/[English]
. link:fr/[French]
```

### GLOSSARY.adoc

This file is used to define terms. [See the glossary section](./lexicon.md).

```asciidoc
= Glossary

== Magic
Sufficiently advanced technology, beyond the understanding of the observer producing a sense of wonder.

== PHP
An atrocious language, invented for the sole purpose of inflicting pain and suffering amongst the programming wizards of this world.
```