Since it was first pointed out by McCarthy and Hayes  that the frame problem was an obstacle to the formalization of dynamic world modelling, reasoning about action has been widely studied in AI community. A number of theories and methodologies for reasoning about action have been proposed to attack the frame problem and other related problems, such as ramification and qualification problems. So far, some important issues of reasoning about action have been identified and well understood by researchers, eg. the temporal projection problem, while other issues are still being widely investigated, eg. indeterminate actions, causality in actions, concurrent actions, natural actions, etc. One common purpose for the research on action theory is to formalize the procedure of reasoning and representing the effect of actions in a more realistic environment from both foundational and computational aspects.