Gauge-Yukawa Unification and The Top Quark Mass

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.