use the following to apply the transformation and result xml will be in your bin path. Open up the result xml file in a browser for a preview or use and webbrowser control to open your xml file.
using System.Xml;
using System.Xml.Xsl;
XslTransform myXslTransform;
myXslTransform = new XslTransform();
myXslTransform.Load("books.xsl");
myXslTransform.Transform("books.xml", "ISBNBookList.xml");