We provide an overview of three ways in which the expression ‘Historical epistemology’ (HE) is often understood: (1) HE as a study of the history of higher-order epistemic concepts such as objectivity, observation, experimentation, or probability; (2) HE as a study of the historical trajectories of the objects of research, such as the electron, DNA, or phlogiston; (3) HE as the long-term study ...