The origin of this monograph is a thesis entitled ‘Frontiers of the Plasmasphere’ that I submitted in 1985 at the Université catholique de Louvain in fulfillment of the ‘Agrégation de l'Enseignement Supérieur’. This D.Sc. thesis described a new physical theory for the formation of the plasmapause.

As a result of this work, Professor M. J. Rycroft, Editor of the Cambridge Atmospheric and Space Science Series, asked me to prepare a monograph on the Plasmasphere. I was honoured by this proposal, but I wanted to decline it in view of the formidable effort that this project would involve, the time that it would take to review the large body of observations as well as the set of controversial theories put forward over twenty years, and then the time needed to compile a comprehensive synthesis all that material. But both the Editor and the Publishing Director of Cambridge University Press (CUP) argued that there was no topical monograph on the Earth's plasmasphere currently on the market and that such a book would be useful in Space Science Laboratories and their Libraries. Since the referees consulted by CUP were also very positive about such a project, I finally accepted.

Of course, a comprehensive monograph on the Earth's plasmasphere should not only describe theoretical aspects as in my thesis. It needed to contain a comprehensive review of the observations collected in the plasmasphere and at the plasmapause. These observations come mainly from whistler as well as from in situ satellite measurements. Only experimentalists who themselves had contributed to observations of the plasmasphere could be responsible for this important part of the monograph.