It is pointed out that an author's violations of ethics can be intentional or unintentional. Sometimes the sins of the pen (or keyboard) creep unawares into a manuscript, only to emerge after publication as awkward ethical problems for the writer. An author can violate accepted standards of practical ethics in several ways. For example, he might run afoul of moral ethics, by misrepresenting facts; professional ethics, by omitting credit to peer's contributions; or legal ethics, by violating copyright laws. Examples show how such indiscretions can damage the author's professional reputation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>