This series contains most of Bernal’s correspondence with individuals and with organisations to which he did not belong. Some correspondence will be found with published papers and in other series if the correspondence is related solely to the material in the file. Where there are a number of letters, or important letters, or letters written before the War, the correspondence has been given a separate named file and these are listed in this series. Other correspondence will be found alphabetically after the named files in each letter of the alphabet. Correspondence with publishers and concerning organization of meetings are in the next two series, K and L.