# Directory Structure

GitBook uses a simple directory structure. All Markdown/Asciidoc files listed in the [SUMMARY](pages.md) will be transformed as HTML. Multi-Lingual books have a slightly [different structure](languages.md).

A basic GitBook usually looks something like this:

```
.
├── book.json
├── README.md
├── SUMMARY.md
├── chapter-1/
|   ├── README.md
|   └── something.md
└── chapter-2/
    ├── README.md
    └── something.md
```

An overview of what each of these does:

| File | Description |
| -------- | ----------- |
| `book.json` | Stores [configuration](config.md) data (__optional__) |
| `README.md` | Preface / Introduction for your book (**required**) |
| `SUMMARY.md` | Table of Contents (See [Pages](pages.md)) (__optional__) |
| `GLOSSARY.md` | Lexicon / List of terms to annotate (See [Glossary](lexicon.md)) (__optional__) |

### Static files and Images

A static file is a file that is not listed in the `SUMMARY.md`. All static files, unless [ignored](#ignore), are copied to the output.

### Ignoring files & folders {#ignore}

GitBook will read the `.gitignore`, `.bookignore` and `.ignore` files to get a list of files and folders to skip.
The format inside those files, follows the same convention as `.gitignore`:

```
# This is a comment

# Ignore the file test.md
test.md

# Ignore everything in the directory "bin"
bin/*
```

### Project integration with subdirectory {#subdirectory}

For software projects, you can use a subdirectory (like `docs/`) to store the book for the project's documentation. You can configure the [`root` option](config.md) to indicate the folder where GitBook can find the book's files:

```
.
├── book.json
└── docs/
    ├── README.md
    └── SUMMARY.md
```

With `book.json` containing:

```
{
    "root": "./docs"
}
```