The doctrinal definition of information operations (IO) focuses exclusively on offensive and defensive activities. The paper proposes extending the definition of IO to include information efficacy, then describes a new approach to military planning and execution called anticipatory planning. This approach seeks to merge planning and execution, and replaces reaction to events with anticipation of events, making more effective use of the information that is available during the conduct of military operations. The paper presents a methodology for the development of a prototype decision support system (DSS) for military decision makers, called the Anticipatory Planning Support System (APSS). This DSS facilitates in-depth analysis of the voluminous data that is available to military decision makers during the course of operations. The paper concludes with an example of the application of anticipatory planning to intrusion response operations.