The desire to understand the nature and scale of the universe is as old as humankind. With the understanding that the force of gravity drives the motion of and distribution of matter within galaxies, comes the notion that studying the motion of stars and gas in our Galaxy and others will allow us to understand their contents. Fairly recent observations of the cold hydrogen in our Galactic disk, and similar observations of other spiral galaxies, have shown that the mass contained as luminous matter (stars, gas, etc.) may be as little as 5-10% of all the mass driving its evolution. So, the vast majority of the mass in the Galaxy, and others like it, appears to be completely dark, such that we cannot observe it directly. We detect it only through the tracer motion of luminous mass, like stars. In this talk, I will present a brief history of the dark matter problem, why we believe dark matter is very real and what might constitute the invisible elephant it represents in the small room of the Universe.