Whether it is true or not that not more than twelve persons in all the world are able to understand Einstein&#39;s Theory, it is nevertheless a fact that there is a constant demand for information about this much-debated topic of relativity. The books published on the subject are so technical that only a person trained in pure physics and higher mathematics is able to fully understand them. In order to make a popular explanation of this far-reaching theory available, the present book is published.<br />Professor Lorentz is credited by Einstein with sharing the development of his theory. He is doubtless better able than any other man&mdash;except the author himself&mdash;to explain this scientific discovery.