This article is the introduction of a special issue devoted to Philippe de La Hire (1640-1718). It proposes a quantitative study which shows that the work the scientist carries out within the Royal Academy of Sciences of Paris is essentially concerned with astronomy and physics. He also underlines that there are evolutions, even periodizations, by fields of his scientific activity, which offers a fine vision of the preoccupations and productions of La Hire during his life. This activity is mainly carried out at the Paris Observatory where La Hire lived from 1682 to 1718. This volume then aims to give the essential characteristics of this academic contribution in these two fields, which is still largely unknown, by focusing on the places − especially the Paris Observatory −, forms, translations and spreads of the scientific production, relying in particular on a set of manuscripts kept nowadays in the Library of the Paris Observatory, more specifically the Journals where La Hire recorded almost daily his astronomical and meteorological observations.