--- - |2 Abstract Surveillance is one of the key aspects of the economic and social system in which we live. Its relevance is growing, due in part to technical advances and in part to complex social dynamics and the magnitude of certain conflicts. In this article we discuss the analytical framework formulated by Bauman, in which he contrasts the concepts of liquid and solid surveillance, and we introduce the concepts of inquisitive and coercive surveillance. We examine the genesis and evolution of both types of surveillance by analyzing public health and penitentiary strategies, particularly in 19th century Spain, as well as those of their respective institutions—the hospital and the prison—with special focus on their spatial manifestations and the divergence between the paths taken in the health‐care and penitentiary spheres. - 'Journal of Historical Sociology, EarlyView. '