This contribution introduces the Handbook of Parliamentary Studies. It first discusses the notion of ‘parliamentary studies’ before outlining the rationales for this editorial project and presenting its main findings, such as commonalities across a variety of disciplinary approaches, a recent renewed interest in legislatures’ rules and the resiliency of parliaments as institutions. After having presented the topic addressed by each contribution, the chapter emphasises the historical as well as conceptual affinities between parliamentarianism and encyclopaedism – an affinity that calls into question the current status of each apparatus.