All types of organizations, for profit, not-for-profit, lawful, and unlawful, must be relentless in highly competitive, and constantly evolving environments. Every day iconic brands like Sears, Kodak, and Blockbuster vanish. Managers in lawful companies face disruptive technologies, groundbreaking new products, and competition from new entrants. Every organization must manage its way through a rapidly shifting world, or else fail. Yet some organized crime syndicates last decades despite massive law enforcement efforts and rival gangs directed at their daily demise. The American Mafia, which burgeoned during Prohibition in the 1920s, still operates in the twenty-first century. The Sinaloa Cartel remains the largest smuggler of drugs into the US, despite jailing its leader, El Chapo Guzmán, in a US supermax prison. How do these criminal syndicates survive, and even thrive? They apply fundamental economic principles to devise management practices that channel their heinous members' self-interest to achieve the syndicates' objectives. Relentless uses the most unexpected organizations, crime syndicates, to elucidate essential economic concepts that allow all leaders to build stronger, more robust companies. These concepts align the organization's business strategy and employee empowerment, incentives, and corporate culture. These principles attract the right people to create resourceful, market-obsessed, and relentless high-performance teams. Understanding the management practices devised by mobsters illustrates the economic concepts that lawful managers also must heed. While lawful managers cannot simply follow the business practices of mobsters, they must apply the same fundamental principles described in Relentless .