This chapter explores the emerging concept of Sixth-Party Logistics (6PL), representing the next evolutionary step beyond established logistics frameworks. 6PL envisions a transformation of logistics providers from digital ecosystem architects to cognitive network orchestrators, leveraging advanced technologies such as cognitive computing, quantum technologies, and artificial intelligence to create self-aware, self-healing supply chains. Through comprehensive frameworks and speculative case studies, the chapter maps the critical dimensions of cognitive intelligence, network complexity, and adaptive capability that define 6PL operations. The author examines how quantum-enhanced optimization, cognitive decision systems, network self-evolution, and predictive risk mitigation form the cornerstones of this future logistics paradigm. While recognizing that full 6PL implementation remains conceptual, the chapter provides practical implementation roadmaps and identifies precursor capabilities already emerging in pioneering organizations. Ethical considerations surrounding autonomous decision-making, data governance, and human-AI collaboration are also addressed, offering organizations a comprehensive guide to navigating both technological and organizational challenges on the path toward cognitive supply chain networks.