Michael Friedjung Though known since antiquity, novae are still poorly under- stood and present many problems. There has tended to be a lack of communication between theoreticians and observers and between different schools of thought, in spite of the advances of recent years in certain directions (observations of ordinary novae at minimum and of dwarf novae, theory of the causes of the explosion, etc *** ). The meeting whose proceedings are contained in this volume was organized to stimulate a confron- tation between the different ideas and results. The subject has changed a lot since 1963,...