This chapter provides a systematic summary of the guiding idea represented by the concept of human dignity in Immanuel Kant. It briefly discusses the question about which insights from Kant's philosophical contribution are systematically important, so that some important conclusions can be drawn which are relevant for contemporary debates in bioethics and constitutional law. The definition of "dignity" presented by Kant in his first ethical text published in 1785, The Groundwork of the Metaphysics of Morals, is widely known and frequently cited both in philosophy and law: In the kingdom of ends everything has either price or dignity. Using the semantic clarification in the Kantian sense, it is possible to reject the understanding of dignity in the sense of a mere granting of preeminence to human beings, avoid a supposed prejudice based on speciesism, and refuse a merely subjective preference.