Introduction: A new gravity theory --; Prologue: The elusive planet Vulcan, a parable --; Discovering and reinventing gravity --; The Greeks to Newton --; Einstein --; The standard model of gravity --; The beginnings of modern cosmology --; Dark matter --; Conventional black holes --; Updating the standard model --; Inflation and variable speed of light (VSL) --; New cosmological data --; Searching for a new gravity theory --; Strings and quantum gravity --; Other alternative gravity theories --; Modified gravity (MOG) --; Envisioning and testing the MOG universe --; The pioneer anomaly --; MOG as a predictive theory --; Cosmology without dark matter --; Do black holes exist in nature? --; Dark energy and the accelerating universe --; The eternal universe.