It is well known that the equation E = mc² comes from the Theory of Relativity. But hardly anyone knows that there is also a simple proof for this relation which Einstein himself derived from the laws of Classical Physics. This was the first step on the direct path to the Theory of Relativity. Now this path, ignored for more than a hundred years, has been followed up. It turns out that the Equivalence Principle Energy-Mass E = mc², in conjunction with Newton's Second Law of Dynamics, provides an easily comprehensible approach to Relativistic Mechanics. The study "Newton and Relativity" shows the amazing results of this investigation. The authors: Dr. Ing. Francesco Cester Dr. rer. nat. Manfred Clemente Dr. rer. nat. Hans-Michael Korff E-Mail: NewtonAndRelativity@gmx.de