Why are the proton’s constituents confined? Where does its mass come from? What makes up its spin? The theory of the strong force, QCD, has proven strikingly successful (e.g. this year’s Nobel Prize), however, so far it cannot be used to understand these fundamental questions. We have begun an experimental program at Brookhaven National Laboratory utilizing the Relativistic Heavy Ion Collider (RHIC) to explore these fundamental questions. In this talk I will motivate the RHIC physics program and discuss the latest experimental results.