<!doctype html public «-//w3c//dtd html 4.0 transitional//en»> http-equiv=content-type> This volume offers a novel and understandable formulation of entropy, a key concept of thermodynamics. Traditional approaches to the derivation of entropy do not make it easy to comprehend this important dimension in thermodynamics. The Entropy Principle presents a significantly improved derivation and structured formulation of entropy that is well suited for basic university education.