  In  McCarthy 1993a,  McCarthy urges us, when considering the early history of circumscription, to take into account a group of three papers: McCarthy  1986,  1980,  and  1987.  The first paper connects the strategic ideas of  McCarthy &amp; Hayes 1969  with the need for a nonmonotonic logic, and sketches the logical ideas of domain circumscription, which is now classified as the simplest case of circumscription. The second paper provides more thorough logical foundations, and introduces the more general and powerful predicate circumscription approach. The third paper concentrates on developing techniques for formalizing challenging common sense examples.