  The principles of finiteness and reduction of couplings can be applied to
achieve Gauge-Yukawa Unification. It is found that the observed top-bottom
hierarchy and the top quark mass naturally follow if there exists Gauge-Yukawa
Unification which is a simple functional relation among the gauge coupling and
the Yukawa couplings of the third generation in various susy unified gauge
models. We briefly outline the basic idea of these principles and present the
main results of the Gauge-Yukawa Unified models that have recently been studied
in detail.
