The chapter discusses the strategic importance of information systems (IS) as competitive weapons, particularly in the context of the customer resource life cycle (CRLC). It highlights how IS can enhance a company's competitive advantage by changing its product or business model. The Harvard Business School's research, based on Michael Porter's theory of competitive forces, emphasizes the role of IS in building defenses against these forces and formulating competitive strategies. The CRLC model, which focuses on the relationship between a company and its customers, provides a detailed framework for identifying and developing strategic IS applications. The model suggests that IS can assist in differentiating a company's products through enhanced customer service, becoming a low-cost producer, or finding a specialized niche. Examples from various industries illustrate how IS can support different stages of the CRLC, from establishing requirements to maintaining and disposing of resources. The chapter concludes that strategic IS applications can significantly impact a company's competitive position and customer loyalty.The chapter discusses the strategic importance of information systems (IS) as competitive weapons, particularly in the context of the customer resource life cycle (CRLC). It highlights how IS can enhance a company's competitive advantage by changing its product or business model. The Harvard Business School's research, based on Michael Porter's theory of competitive forces, emphasizes the role of IS in building defenses against these forces and formulating competitive strategies. The CRLC model, which focuses on the relationship between a company and its customers, provides a detailed framework for identifying and developing strategic IS applications. The model suggests that IS can assist in differentiating a company's products through enhanced customer service, becoming a low-cost producer, or finding a specialized niche. Examples from various industries illustrate how IS can support different stages of the CRLC, from establishing requirements to maintaining and disposing of resources. The chapter concludes that strategic IS applications can significantly impact a company's competitive position and customer loyalty.