  The discovery of extensive air showers by Rossi, Schmeiser, Bothe,
Kolh\"orster and Auger at the end of the 1930s, facilitated by the coincidence
technique of Bothe and Rossi, led to fundamental contributions in the field of
cosmic ray physics and laid the foundation for high-energy particle physics.
Soon after World War II a cosmic ray group at MIT in the USA pioneered detailed
investigations of air shower phenomena and their experimental skill laid the
foundation for many of the methods and much of the instrumentation used today.
Soon interests focussed on the highest energies requiring much larger detectors
to be operated. The first detection of air fluorescence light by Japanese and
US groups in the early 1970s marked an important experimental breakthrough
towards this end as it allowed huge volumes of atmosphere to be monitored by
optical telescopes. Radio observations of air showers, pioneered in the 1960s,
are presently experiencing a renaissance and may revolutionise the field again.
In the last 7 decades the research has seen many ups but also a few downs.
However, the example of the Cygnus X-3 story demonstrated that even
non-confirmable observations can have a huge impact by boosting new
instrumentation to make discoveries and shape an entire scientific community.
