A successful geophysicist must learn how to create a
model simple enough for the application of principles of
mathematical physics, and yet capable of capturing the
essence of the phenomena in the Earth. In the past,
geophysicists tended to restrict themselves to either a study
of structure or a study of procesa The time has come to
combine these two lines of study for better understanding of
phenomena in the Earth. This volume represents an initial
effort toward this goal by providing a survey of such
modeling of geophysical structures and processes covering
the whole Earth from its ionosphere to the i~er core.