Why do John Lithgow and his wife have different last names?
Well, many women today do not change their names when married, of course. But on top of that, historians (and other writers) often become known by their name. When Mary Yeager wrote her second book, or her third, or fourth, she wanted to make sure people knew it was by the same person that wrote her first book. If she changed names, people might not realize that fact.
