The eerie flickers of auroras have inspired awe since times immemorial. They kindled the fears and superstitions of people in the prescientific era and the curiosity of inquiring minds since. Yet it is only since the arrival of the space age that a full physical understanding has been reached. This has probably stimulated not only substantial journal literature but a number of books which trace the development of that understanding from the supernatural to phenomenology to a reasonably complete physical model. AGU published the work of Eather , and the Nordic experience and contribution is superbly reflected in the treatise of Brekke and Egeland . A somewhat more theoretical framework is offered by Volland .