This book has argued that the problem of integrating science into democracy is fundamentally a practical and political challenge of authority, not merely an epistemological issue of trust or deference. Beginning with a Kantian constructivist framework, it established that any legitimate authority for science must be grounded in the principles of public reason and citizen autonomy. The analysis then proceeded with a systematic critique of the three dominant models—trust, epistemic authority, and democratic authority—demonstrating that while each is a necessary component, they are individually insufficient because they fail to adequately address the profound challenge of hyper-specialization. This core problem fragments knowledge and makes substantive public judgment seem impossible. The book’s central contribution has been to offer a novel framework and synthesis that resolves this dilemma. By advocating for the institutionalization of “trading zones” and the cultivation of “interactional expertise,” it provides a concrete mechanism for bridging epistemic divides. This approach completes the democratic authority model by enabling the substantive, reason-based public criticism necessary for its legitimacy, thereby offering a robust framework for preserving both scientific integrity and democratic self-governance in an age of complexity.