A nasty e-mail written about you by a co-worker could be the basis of a case of defamation, or libel, against that person. Libel occurs when 1) someone makes a false statement of fact in writing, 2) someone else reads the statement, and 3) the statement harms your reputation. In the case of e-mail, it’s generally clear that someone has written a statement and someone else has read it. To win in court, you also must prove the e-mail harmed your reputation. In response, valid defenses the co-worker might assert are that the statements are either true or are merely the writer’s opinion.