The book is a selection of public lectures given at three different Rencontres internationales de Genève in 1952, 1957 and 1958, as follows [chronological order]:

• Erwin Schrödinger, 1952, delivered in German, published in original German plus a French summary, as 'Unsere Vorstellung von der Materie', in Rencontres internationales de Genève vol. 7, L'Homme devant la science, Les Éditions de la Baconnière, Neuchâtel, 1952, pp. 31-54.
  
• Pierre Auger, 1952, delivered and published in French as 'Les méthodes et les limites de la connaissance scientifique.' at the same conference/same publication as Schrödinger's, pp.55-80.
  
• Max Born, 1957, delivered in German, published in French translation as 'Réflexions d’un homme de science européen' in Rencontres internationales de Genève vol. 12, L'Europe et le Monde d'Aujourd'hui, Les Éditions de la Baconnière, Neuchâtel, 1958, pp. 29-48; original German appeared as 'Europäische Betrachtungen eines Naturforschers', Universitas, 13/3, S.225-240, Stuttgart 1958
  
• Werner Heisenberg, 1958, delivered in German, published in original German plus a French summary, as 'Die Plancksche Entdeckung und die philosophischen' in Rencontres internationales de Genève vol. 13, L'Homme et l'atome, Les Éditions de la Baconnière, Neuchâtel, 1958, pp. 37-60; debate pp. 189-203.

The electronic versions of all Rencontres are publicly available as text pdfs (not facsimiles). See "Links" section.