The Paper Archive and Library of CRA-CMA (Agricultural Research Council – Research Unit for Climatology and Meteorology applied to Agriculture) are an important source of meteorological data for climate research. CRA-CMA's Paper Archive gathers a collection of about 850 historical meteorological datasets. Among them, 40 are nowadays still in progress, 260 are more than thirty years long and 20 exceed one century. Moreover, the specialized Library of CRA-CMA gathers several publications containing meteorological data from many Italian and foreign observatories and an important collection of scientific journals and historical books on Atmospheric Sciences, Geophysics and Agrometeorology published both in Italy and abroad and dating from the second half of the sixteenth century. Even if input data for climate models are generally based on 30 yr long datasets, nevertheless longer observational series (up to 50 or 100 yr) are a key element to better understand the climate system behavior. Until today, the library described in this paper is a CRA-CMA heritage almost unknown to the international scientific community.