The importance of physics and mathematics in astronomical research has been growing for the last twenty years; yet, the volume of book acquisitions in the relating fields has been decreasing in most french libraries specialized in astronomy (graph 1).

Great are the consequences of the physics book high prices (graph 2) on the acquisition volume and more drastic is the selection when the total amount of acquisitions is low, i.e. in small libraries (graphs 3 and 4). Yet, the restriction of acquisitions has not generated increasing inter-library loans in the relating fields and national service (CADIST) acquisitions in physics and mathematics have also been dropping. This point, connected with the concomitant general growth of astronomical book accessions, leads us to explain the contradictory observations as mentioned above here from the astronomical publication contents.