This book has found out the explicit answers to the following BIG questions that have been hovering over and lingering around dark matter for a long time. -Is there new theory showing, with conclusive or hard evidence, that a cluster of dark matter turns out to be a hugely massive celestial body, much more massive than an ordinary celestial body? -What are the fundamental constituents of dark matter? Or are the fundamental elements that make up the constituents of dark matter the same as other ordinary celestial bodies? -Is the gravitational nature of dark matter the same as other ordinary celestial bodies, though the gravitational effects caused by a cluster of dark matter, due to its hugely massive feature, are much stronger than an ordinary celestial body? -After unveiling the mystery of dark matter, including its constituents and fundamental nature, does dark matter turn out to be amazingly simple or extremely complicated? -Above all, what is the mechanism and essence of dark matter? Narrator: but more than that, this book reveals and shows that the unveiling of the mystery of dark matter depends on the newly developed and verified gravitational theory that has solved the fundamental problem of why time runs slower in a gravitational field by revealing the mechanism behind this why. This book also digs out and analyzes the root cause of why Einstein's theory of general relativity turns out unable to unveil the mystery of dark matter. (Commentator) as a result, what this book has unfolded is closely related to such a famous quote from Einstein: "no problem can be solved from the same level of consciousness that created it." Correspondingly, the displayed fact or concept in this book is: the development of science needs to discover new theories by new modes of thinking and by breaking through or surpassing the conventional level of consciousness, in order to solve the new problems that have not been and cannot be solved by conventional theories.