This comprehensive chapter explores the evolving landscape of human–AI interaction through the lens of large language models, examining how these technologies are transforming from mere tools to cognitive partners. Beginning with fundamental cognitive science principles that underpin effective human–AI collaboration, the chapter navigates through the technical capabilities enabling sophisticated interactions, the challenges of aligning AI systems with human values, and practical applications across professional domains. Drawing from interdisciplinary research spanning cognitive psychology, computer science, and ethics, the text presents frameworks for designing AI systems that enhance human capabilities while preserving human agency and judgment. The chapter culminates in an examination of future directions, emphasizing how thoughtfully designed human–AI partnerships can foster human flourishing rather than dependency. This work provides both theoretical foundations and practical insights for researchers, practitioners, and policymakers seeking to create AI systems that serve as effective cognitive collaborators while upholding human values and potential.