Published by the American Geophysical Union as part of the Special Publications Series.

Physics of the aurora and airglow is a diversified subject, and this characteristic is, I think, the secret of its charm. But it is growing up in an age when physicists must necessarily specialize in narrow fields of interest. The advantage gained by a scientist applying his particular competence to the aurora or airglow is then partly offset by his lack of familiarity with other areas of the topic. The field is so broad that it is most difficult for him to learn the whole subject while still pursuing and keeping abreast in his own specialty.