It could be something like this:
var story = from entry in stories.Descendants(xmlns + "entry")
from a in entry.Descendants(xmlns + "author")
select new Story
{
Title = entry.Element(xmlns + "title").Value,
Content = entry.Element(xmlns + "subtitle").Value,
Author = new AuthorInfo(
a.Element(xmlns + "name").Value,
a.Element(xmlns + "email").Value,
a.Element(xmlns + "uri").Value
)
};