This chapter digresses from the theoretical study of computation to connect abstract models to hardware, covering transistors, logic gates, and the translation from high-level code to machine instructions. The discussion begins with the manifestation of Boolean logic gates as transistor circuits and progresses toward combinational circuits to add unsigned integers. This approach is shown to be unfeasible, and the discussion pivots toward sequential circuits. A clock signal is presented along with edge detectors and memory elements, which is shown to be a more scalable approach toward building memory and a general-purpose computer. The inner workings of a rudimentary CPU are introduced along with CPU instructions and layers of computer code abstraction. Finally, progress in classical computation is presented with a brief overview of modern computer architecture.