Everyone concerned with the teaching of physics at the advanced undergraduate or graduate level is aware of
the continuing need for a modernization and reorganization
of the basic course material. Despite the existence today
of many good textbooks in these areas, there is always an
appreciable time-lag in the incorporation of new viewpoints
and techniques which result from the most recent developments
in physics research. Typically these changes in concepts and
material take place first in the personal lecture notes of
some of those who teach graduate courses. Eventually, printed
notes may appear, and some fraction of such notes evolve into
textbooks or monographs. But much of this fresh material
remains available only to a very limited audience, to the
detriment of all. Our series aims to fill this gap ln the
literature of physics by presenting occasional volumes with
a contemporary approach to the classical topics of physics
at the advanced undergraduate alld graduate level. Clarity
and soundness of treatment will, we hope, mark these volumes,
as well as the freshness of the approach.