Although this volume is dedicated to honoring Francois Jacob, I would like my contribution to broaden the context by recalling the background within which the scientists of those times operated. The specific scientific accomplishments of Jacob will certainly be covered by the other contributors who collaborated with him. My handful of recollections presented here largely as vignettes is intended to give the reader a feeling for the elements, many social, that shaped the generation of scientists that included such central figures, Jacob, Lwoff, Monod. It is the tale of a generation trying to express its creativity in a world caught up in war, irrational values and unforgivable inhumanity. Even this limited account is a great story bringing us important lessons for thought. (C) 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.