This book includes volumes I and II of the Theory of Global Equivalence. In the first volume of this theory of everything: • Perspectives of modern science and metaphysics are combined. • The different definitions of time are discussed, emphasizing the subjective origin of the concept and the never-ending attempts to obtain its common and objective idea. • The book attempts to replace the correct duality of subjective and objective reality in the realm of philosophy, separating them from other, let s say, imaginary realities. • The new theory of everything is presented from a strictly scientific point of view. The second volume explains the basic concepts of Einstein's Theory of Relativity, analyzing: • Maxwell's equations and the Lorentz transformations, the principles of Poincaré and interpretations of the Michelson-Morley experiment as immediate antecedents of relativistic physics. • Physical principles and postulates of Einstein's relativity. • The geometry of Euclidean space and types of space in Einstein s theory with reference to the geometry of space of Minkowsky and Riemann. • Concept of inertial, gravitational and relativistic mass. • Principle of equivalence incorporating gravity in General Relativity and the twin paradox.