This thesis argues that fiduciary relationships have a coherent and principled rationale grounded in freedom. Specifically, it is argued that fiduciary relationships may be understood in terms of Kant's third category of private right, rights to persons akin to rights to things. The fiduciary duty of loyalty, the conflict and profit rules, the role of deterrence and the effects of consent and disclosure in the law of fiduciaries are all explored and are argued to fit within the logic of this right. The argument put forward here implies that the classification of the fiduciary obligation is categorically distinct from that of contract and property.