This book is unique in the following senses: First, it provides three different, but equivalent definitions of Entropy. Second, it provides a simple, valid, and proven interpretation of Entropy, and the Second Law of Thermodynamics based on Shannon's Measure of Information. Third, this is the only book that proves that Entropy is not a function of time. It also shows that Clausius had over-generalized when he formulated the Second Law, and that Boltzmann, misinterpreted his own H-Theorem.