The Difference between Theory and Practice is greater in practice then it is in theory. We are on the brink of our first official release of Shenandoah. It took two weeks to write up the design and over two years to implement it. This talk will discuss the differences between what we initially proposed and what we now have working. An honest look at compromises, wrong turns, and innovations. We will finish the talk with the theory of what comes next: A high level design for NUMA aware GC, a sketch of a plan for truly pauseless GC, a brief consideration of reference counting...