The correspondents are:
Dr Leo Sachs ("The areas that Sydney [Brenner] and I find attractive are ..."), Dr Carl Sagan, Professor Abdus Salam (Rattan Singh Mann), Dr S Samueloff, Anne Sayre, Dr Brian Schaffer, Dr Kenneth F Schaffner, Dr Eduardo Scarano, Dr Peter Schell, Dr Jakob Schmidt (AG base pairing), Lewis L Schock Jr, Dr Harold L Segal, G P Serjak, Dr C A Setterstrom, Brian Shaffer, Pukh Raj Sharma, Dr R G Shulman (acridine mutants), Dr Obind Siddiqi, Rubert Siemerling, Dr John D Simnett, Dr Maxine Singer, Dr Hayes Slaughter, Dr Emil Smith, Professor John Maynard Smith, Dr F C Steward, Professor K M Smith, Dr Oliver Smithies, Lord Snow ('Social impact of biology'), Professor T M Sonneborn (social impact of biology, including Sonneborn papers), Arnold J Soderberg, Dr W D Stein (facilitated diffusion), Professor Sherman Stein, Dr A Steinschneider, Dr Joan Argetsinger Steitz, Dr Gunther Stent, Dr F C Steward (morphogenesis), R D B Stocker, Navin Sullivan (Thomas Nelson & Sons Ltd), and Dr Gertrud Weiss Szilard.