Supererogation (roughly, going beyond the call of duty or doing more than one must) is a familiar part moral consciousness, and it is one member of a rich family of associated concepts that have proved challenging to adequately model collectively in deontic logic, as well as ethical theory. Much of the work done, especially earlier work, important as it is, was at the cusp of logic and ethical theory, with this early work having only sketches of logical frameworks and no formal semantics. Only a small body of work from the late 1980s forward meets minimal standards one comes to expect in deontic logic. This essay surveys much of that earlier work in the 1960s and 1970s, regimenting and developing that work, and evaluating it, and then turns to subsequent more sophisticated work, expositing, at times developing, and evaluating that work. The result is an overview of this underdeveloped area, and an invitation develop it further. It also serves as a case study of how work in deontic logic can be highly relevant to ethical theory.
