Abstract
The 1912 balloon flights of Victor Hess and related activities in those years are reviewed. Subsequent research during the early 20th Century is noted, including the discovery of the positron, mesons, and air showers. The cosmic ray–accelerator interrelations are noted, including cosmic ray studies at Echo Lake and Mt. Evans, Colorado (USA). The more recent evolution of cosmic ray research programs to astrophysical and cosmological studies, and the major programs such as Auger and AMS conclude this discussion of the century of cosmic ray research.
