King and Eye explores the visual formation of kingship in Siam in its multifarious aspects. This dissertation identifies the leitmotifs in the dynamics between seeing the king and being seen by him, which burst forth in different eras. The visual sense has been a repository for the ontologization of the state, that is, for determining what exists in its purview, what constitutes its reality, and, implicitly, what is excluded from it. The shift in the formation of the sense means the transformation of the state. More specifically, it examines the relationship between the monarchy and various optical devices, most significantly the photographic and the cine cameras, but also encompassing other ocular apparatuses. The images produced through the contraptions were brought together under the royal eye at the apex, which in turn claimed its supremacy over space, time, and the vast and diverse population. On the other hand, they were commonly pervaded by the images of the royal body, which was increasingly exposed via the cameras. With the focus on photography and cinema, the bulk of the content lies in the nineteenth- and early twentieth-century Siam.