diff --git a/docs/Document.md b/docs/Document.md
new file mode 100644
index 0000000..e675785
--- /dev/null
+++ b/docs/Document.md
@@ -0,0 +1,243 @@
+# Document
+A copy of the Document class from `libxmljs` with extra methods and existing ones modified.
+
+## Constructor
+### new Document(source = null, type = Document.TYPE_XML, options = null);
+>Creates a new `Document`.  
+
+>**args**  
+*source*: `string` (optional) - The source as a string.  
+*type*: `number` (optional) - The type of the `Document`.  
+*options*: `libxmls.ParserOptions` (optional) - The parser options.  
+
+
+## Properties
+
+### static TYPE_XML: `number`
+>Describe the `Document` as an XML document.  
+
+>**value**  
+0
+
+
+### static TYPE_HTML: `number`
+>Describe the `Document` as an HTML document.  
+
+>**value**  
+1
+
+
+### static TYPE_HTML_FRAGMENT: `number`
+>Describe the `Document` as an HTML fragment.  
+
+>**value**  
+2
+
+
+### _original: `libxmljs.Document|null`
+>The internal `libxmljs.Document` instance.
+
+
+### _hasContent: `boolean`
+>Tells whether the `Document` has content.
+
+
+### namespace: `object|null`
+>The object that holds the namespace information.
+
+
+### errors: `SyntaxError[]`
+>An array containing the errors in the current `Document`.
+
+
+### validationErrors: `ValidationError[]|undefined`
+>An array containing the validation errors in the current `Document`.
+
+
+## Methods
+
+### child(idx): `libxmljs.Element|null`
+>Gets the idxth child of the root node.  
+
+>**args**  
+*idx*: `number` - The child index.  
+
+>**returns** A `libxmljs.Element` or `null`.
+
+### childNodes(): `libxmljs.Element[]`
+>Gets all the children of the root node.  
+
+>**returns** An array of `libxmljs.Element`s.
+
+
+### count(xpath): `number`
+>Counts the amount of results of the provided XPath.  
+
+>**args**  
+*xpath*: `string` - The XPath to count.  
+
+>**returns** The amount of results.
+
+
+### encoding(): `string`
+>Gets the `Document`'s encoding.  
+
+>**returns** The `Document`'s encoding.
+
+
+### encoding(enc): `Document`
+>Sets the `Document`'s encoding.  
+
+>***args**  
+*enc*: `string` - The encoding as a string.
+
+>**returns** The `Document`.
+
+
+### find(xpath): `libxmljs.Element[]`
+>Finds the result of the provided XPath.  
+
+>**args**  
+*xpath*: `string` - The XPath to find.  
+
+>**returns** An array of `libxmljs.Element`s.
+
+
+### fromHtml(html, options = {}): `Document`
+>Parses an HTML document.  
+
+>**args**  
+*html*: `string` - The HTML content.  
+*options*: `libxmljs.ParserOptions` (optional) - The parser options.  
+
+>**returns** The `Document`.
+
+
+### fromHtmlFragment(htmlFragment, options = {}): `Document`
+>Parses an HTML fragment.  
+
+>**args**  
+*htmlFragment*: `string` - The HTML content.  
+*options*: `libxmljs.ParserOptions` (optional) - The parser options.  
+
+>**returns** The `Document`.
+
+
+### fromXml(xml, options = {}): `Document`
+>Parses an XML document.  
+
+>**args**  
+*xml*: `string` - The XML content.  
+*options*: `libxmljs.ParserOptions` (optional) - The parser options.  
+
+>**returns** The `Document`.
+
+
+### get(xpath): `libxmljs.Element`
+>Gets the first result of the provided XPath.  
+
+>**args**  
+*xpath*: `string` - The XPath to get.  
+
+>**returns** A `libxmljs.Element`.
+
+
+### getDtd(): `object`
+>Gets the `Document`'s DTD.  
+
+>**returns** The DTD object.
+
+
+### namespaces(): `libxmljs.Namespace[]`
+>Gets the `Document`'s namespaces.  
+
+>**returns** An array of `libxmljs.Namespace`s.
+
+
+### node(name, content): `libxmljs.Node`
+>Creates the root.  
+
+>**args**  
+*name*: `string` - The root's tag name.  
+*content*: `string` - The root's text content.  
+
+>**returns** The created `libxmljs.Node`.
+
+
+### rngValidate(rng): `boolean`
+>Checks whether the `Document` is valid using Relax NG.  
+
+>**args**  
+*rng*: `object` - The Relax NG.  
+
+>**returns** Whether the `Document` is valid using Relax NG.
+
+
+### root(): `libxmljs.Element|null`
+>Gets the root.  
+
+>**returns** The root or `null`.
+
+
+### root(node): `libxmljs.Element`
+>Sets the root.  
+
+>**args**  
+*node*: `libxmljs.Element` - The root `libxmljs.Element`.  
+
+>**returns** The created `libxmljs.Element`.
+
+
+### setDtd(name, ext, sys): `Document`
+>Sets the `Document`'s DTD.  
+
+>**args**  
+*name*: `string` - The name of the DTD.  
+*ext*: `string` - The external ID for the DTD.  
+*sys*: `string` - The system ID for the DTD.  
+
+>**returns** The `Document`.
+
+
+### setNamespace(alias, url): `Document`
+>Sets the `Document`'s namespace.  
+
+>**args**  
+*alias*: `string` - The alias of the namespace.  
+*url*: `string` - The URL of the namespace.  
+
+>**returns** The `Document`.
+
+
+### toString(formatting = true): `string`
+>Returns the `Document` as a string.  
+
+>**args**  
+*formatting*: `boolean` (optional) - Tells whether the ouput is formatted.  
+
+>**returns** The `Document` as a string.
+
+
+### type(): `string`
+>Returns the string "document".  
+
+>**returns** "document".
+
+
+### validate(xsdDoc): `boolean`
+>Validates the `Document` against a XSD document.  
+
+>**args**  
+*xsdDoc*: `Document` - The XSD `Document`.  
+
+>**returns** Whether the `Document` is valid. `validationErrors` contains the errors if any.
+
+
+### version(): `string`
+>Gets the `Document`'s version.  
+
+>**returns** The `Document`'s version.
+
+
+### assertNoContentError(): `void`
+>Throws an error if the `Document` has no content.
diff --git a/src/Document.js b/src/Document.js
index 6fd90de..254d002 100644
--- a/src/Document.js
+++ b/src/Document.js
@@ -73,7 +73,7 @@
 
   /**
    * Gets the idxth child of the root node.
-   * @param {number} idx
+   * @param {number} idx The child index.
    * @returns {libxmljs.Element|null} A `libxmljs.Element` or `null`.
    */
   child(idx) {
@@ -86,7 +86,7 @@
 
   /**
    * Gets all the children of the root node.
-   * @returns {Element[]} An array of `libxmljs.Element`s.
+   * @returns {libxmljs.Element[]} An array of `libxmljs.Element`s.
    */
   childNodes() {
     this.assertNoContentError();
@@ -115,7 +115,8 @@
 
   /**
    * Sets the `Document`'s encoding.
-   * @returns {string} The `Document`.
+   * @param {string} enc The encoding as a string.
+   * @returns {Document} The `Document`.
    */
   encoding(enc) {
     this._original.encoding(enc);
@@ -266,10 +267,12 @@
    * @param {string} name The name of the DTD.
    * @param {string} ext The external ID for the DTD.
    * @param {string} sys The system ID for the DTD.
-   * @returns {void}
+   * @returns {Document} The `Document`.
    */
   setDtd(name, ext, sys) {
-    return this._original.setDtd(name, ext, sys);
+    this._original.setDtd(name, ext, sys);
+
+    return this;
   }
 
   /**
@@ -293,7 +296,7 @@
 
   /**
    * Returns the `Document` as a string.
-   * @param {boolean} formatting Tells whether the ouput is formatted.
+   * @param {boolean} [formatting] Tells whether the ouput is formatted.
    * @returns {string} The `Document` as a string.
    */
   toString(formatting = true) {