  The problem of calculating the effective potential for a real scalar field
with a double--well potential is a possible preliminary to understanding
symmetry breaking phase transitions in the early universe. It is argued here
that it is necessary to include multiple saddle points in the path integral
formalism and that quadratic source terms are important. The resulting
effective action has a well--defined propagator expansion with a positive mass
and gives a new way of understanding high temperature expansions, but the
results are equally valid at low or zero temperatures.

High Energy Physics - Phenomenology