This book gives a general overview of Grand Unification Theory (G.U.T.). GUT is a theory that is modeled around The Standard Model of High Energy Particle Physics. The strict form of GUT seeks to model the combination of three out of four of the currently observed fundamental forces into a single force. GUT tries to unite the electromagnetic, the weak and the strong force into one theory or model. If all three of these forces are then united with gravity, this is regarded to be a Theory of Everything (T.O.E.). In this perspective, Grand Unification Theory is an intermediate step towards producing a Theory of Everything. This is one of the ultimate goals of math, physics and cosmology.This book is designed to be a reference and provide an overview of the topic and give the reader a structured knowledge to familiarize yourself with the topic at the most affordable price possible.The accuracy and knowledge is of an international viewpoint as the edited articles represent the inputs of many knowledgeable individuals and some of the most current knowledge on the topic, based on the date of publication.