Save a Document to a file in CSharp

/*from w  ww .j av a  2 s.  c  om*/
using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {


        XDocument xDocument = new XDocument(
         new XElement("Books",
           new XElement("Book",
           new XAttribute("type", "Author"),
           new XAttribute("experience", "first-time"),
           new XAttribute("language", "English"),
           new XElement("FirstName", "J"),
           new XElement("LastName", "R"))));

        xDocument.Save("book.xml");
    }
}