I wrote this book for my friends who are not physicists, but who are curious about the physical world and willing to invest some effort to understand it. I especially had in mind those who labor to make the work of physics possible – technical workers in other fields, teachers, science-minded public officials – who read popular accounts but are hungry for a “next step” that might give them a firmer grasp of this puzzling material. Physics gives me great pleasure, more from its beauty than from its usefulness, and I regret that my enjoyment should depend on the effort of so many others who do not share it. Here I have tried to ease my sense of guilt by attempting to disclose in ordinary language what modern physics really is about. Many similar accounts exist. In this one, I attempt to demystify the deep ideas as much as possible in a nonmathematical treatment. Some mathematical ideas are inevitable, and these I try to explain. Physics has entered an exciting phase with talk of new dimensions, exotic matter, and mind-boggling events of cosmic scale. These dramatic ideas rest on a solid conceptual framework, a product of the last century that is now old hat for physicists but remains exotic and impenetrable to most others. This framework, quantum theory and the Standard Model of matter, is an intellectual achievement of the highest order and essential for understanding what comes next. My intention here is to provide a reference and a guide to this known but still regrettably unfamiliar world.