As the National Counterintelligence and Security Center (NCSC) strategy states, “The United States is facing threats from foreign intelligence entities (FIEs) that are unprecedented in their breadth, volume, sophistication, and impact.” The DIB is under assault from FIEs seeking to steal U.S. defense innovation and technology. Through our Playbook, Sphinx unites cyber, personnel security (PERSEC), and counterintelligence (CI) methods to enable DIB firms to protect their investments against multi-domain threats that blend traditional espionage, insider risk, supply chain infiltration, and advanced cyber operations.