This book, "Strategic Frameworks for Competitive Advantage: Exploring the X and O Theory in Contrasting Marketing Approaches to Winning Public Contracts: Comparative Study of Two Algerian Contractors," delves into the strategic methodologies employed by private and public enterprises in securing public procurement contracts. Through the innovative lens of the X and O Theory, we analyze the proactive and aggressive strategies of the X Company type against the reactive and defensive approaches of the O Company type. Our comparative study focuses on two Algerian contractors - one private and one public. We explore their sourcing strategies, company presentations, quality assurance, partnerships, market intelligence, brand image, competitive strategies, financial management, marketing, and relationships. By categorizing these companies into subtypes such as XXO, XOX, and OOX, we provide a nuanced understanding of how different strategic blends impact their success in the competitive landscape of public procurement. This comprehensive analysis offers valuable insights for business leaders, strategists, and policymakers.