Time dilation... This concept established in 1905, appeared in a Paper named "special relativity" . Done by the gentlemen EINSTEIN and LORENTZ , this theory was written to unify electromagnetics area and Newtonian mechanics . Einstein subsequently replaced this work by the "General Relativity", to explain universal gravitation. Our first book dedicated to the resolution of the partials differentials equations ("Gradient of time and Partials Differentials Equations"), highlighted the action of the "time dilation" inside all physics phenomenon . At the time , a question remains : Can we use the "gradient of time" to write in a new mind , the general relativity ? The answer is positive . An example of its possibility , is the alternate demonstration in this book , of the famous E = mcý. Much more , we can proove that this last expression , is a special case of an anoither formula . Certainly , this book would give satisfaction to all the fans of science and theoretical innovations.