XML C#

using System;
using System.Linq;
using System.Xml;
using System.Xml.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml.XPath;
public class MainClass
{
    public static void Main()
    {
        XPathDocument document = new XPathDocument("books.xml");
        XPathNavigator navigator = document.CreateNavigator();
        XPathNodeIterator nodes = navigator.Select("descendant::book[author/last-name='E']");
        while (nodes.MoveNext())
        {
            XPathNavigator clone = nodes.Current.Clone();
            clone.MoveToFirstChild();
            Console.WriteLine("Book title: {0}", clone.Value);
        }
    }
}