Every account of the history of science written by practicing scientists is biased toward the authors' experience. This is clearly evident in several articles that have appeared recently recognising the centenary of the discovery of cosmic rays (Carlson 2012 [1], Israel2012 [2], Watson 2012 [3]). We therefore make no apology for this article placing some emphasis on the Australian contribution to the field over the last 100 years.

The first record that could be associated with cosmic rays was reported in Paris in 1785 by Charles-Augustin de Coulomb when he noted that electrically charged objects lost their charge even when well isolated from a discharge path. He concluded that the discharge must be through the air though the mechanism remained a mystery for more than a century. In the late 1800s when various forms of penetrating radiation were discovered it became clear that air could be ionised and allow an electroscope to discharge. However, even heavily shielded electroscopes discharged when all known forms of radiation would not have penetrated the shielding. It was becoming clear that an extremely penetrating ionising radiation from above the earth's surface might be responsible.