Robert A. Heinlein was the most influential science fiction writer of his era, an influence so large that, as Samuel R. Delany notes, "modern critics attempting to wrestle with that influence find themselves dealing with an object rather like the sky or an ocean." He won the Hugo Award for best novel four times, a record that still stands. The Moon is a Harsh Mistress was the last of these Hugo-winning novels, and it is widely considered his finest work.