  This study proposes that all the known fundamental forces including gravity
may be described by local gauge theories. Gravitational, electroweak, and
strong interactions on length scales from 10^{-33} cm to 10^{28} cm are
systematically discussed from the unified gauge theory point of view toward a
ultimate theory for fundamental forces. New concepts such as dynamical
spontaneous symmetry breaking, gauge group hierarchy, coupling constant
hierarchy, effective coupling constant hierarchy, cosmological constant,
massive gauge bosons, massless gauge bosons, quantum weakdynamics, analogy
between quantum weakdynamics and quantum chromodynamics, a possible gauge
theory for the universe expansion, the relation between time and gauge boson
mass, other quantum tests, etc. are briefly reported based on experiments.
