wave-particle dilemma in respect of new physical phenomena.[^4] The Bothe and Kohlhörster experiment was a challenge to the dominant interpretative model, and several physicists started working on cosmic rays. A young Venetian scientist, Bruno Rossi, felt fascinated by the new challenge too, and he soon became an outstanding pioneer in cosmic rays researches. As he wrote years later, he felt “a subconscious feeling for the inexhaustible wealth of nature, a wealth that goes far beyond the imagination of man. That feeling \[…\] was the reason why, as a young man, I went into the field of cosmic rays. In any case, whenever technical progress opened a new window into the surrounding world, I felt the urge to look through this window, hoping to see something unexpected” (cited byGeorge W. Clark in [@Clark1998], p. 311).

The beginnings of cosmic-ray researches in Italy: from the late 1920s to 1945
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Bruno Rossi’s researches from 1929 to 1938
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Born in Venice in 1905, Bruno Benedetto Rossi studied in Padua and Bologna. He started his academic career in 1928 at the University of Florence, where he worked with a group of physicists he particularly appreciated for their scientific and human qualities (fig. 1). The group was composed of Gilberto Bernardini, who was to become one of the prominent scientists of Italian post-war physics, Giulio Racah, Daria Bocciarelli, Lorenzo Emo, Guglielmo Righini, Beatrice Crinò and Giuseppe (Beppo) Occhialini. The latter, who was to carry out fundamental studies on cosmic rays, always considered himself as Rossi’s pupil, though he was only two years younger.

![Bruno Rossi