 Bennett was an internationally known scholar on the life of "Frankenstein" author Mary Wollstonecraft Shelley and her circle of friends.She is best known for her three-volume "The Letters of Mary Wollstonecraft Shelley," which she edited and published from 1980 to 1988.In a 1988 review of Dr. Bennett's final volume of the letters, author Brian Aldiss declared her work "a great contribution to scholarship, and one that never need be done again."