The traditional Festschrift was abandoned for Niels Bohr’s 50^th birthday, lest he should ‘feel it as his duty to read the contents and even try to learn something.’ Instead, he received the Journal of Jocular Physics.

Future Director-General of CERN, Viki Weisskopf, was a major contributor. His ‘Komplementäre Philosophie des Witzes’ (Complementary Philosophy of Jokes) maintained that humour held a curved mirror to truth, giving a distorted but illuminating insight that challenged our comfortable assumptions in much the same way as one of key tenets of quantum mechanics, complementarity.

Published by the Institute of Theoretical Physics (now the Niels Bohr Institute), the spoof journal contained articles in German, Danish, English, French and Japanese and espoused an attitude of ‘hopeful pessimism and serene preparedness’. Sadly, with Europe moving towards World War 2, contributions from G. Gamow, O. Klein (echoing a bellicose speech by Mussolini) and L. Rosenfeld were omitted, as ‘the possibility of misinterpretation in a political and therefore, not purely jocular sense could not be entirely excluded.’