The traditional sense of hopefully, ‘in a hopeful manner’, has been used since the 17th century. In the second half of the 20th century a new use as a sentence adverb became established, meaning ‘it is to be hoped that’, as in hopefully, we’ll see you tomorrow. This second use is now very much commoner than the first use, but it is still believed by some people to be incorrect. Why should this be? People do not criticize other sentence adverbs, e.g. sadly (as in sadly, her father died last year) or fortunately (as in fortunately, he recovered). Part of the reason is that hopefully is a rather odd sentence adverb: while many others, such as sadly, regrettably, and clearly, may be paraphrased as ‘it is sad/regrettable/clear that ...’, this is not possible with hopefully. Nevertheless, it is clear that use of hopefully has become a shibboleth of ‘correctness’ in the language—even if the arguments on which this is based are not particularly strong—and it is wise to be aware of this in formal contexts.