Modern day electronic devices are reaching nanometer dimensions where atomistic effects are dominant. Fundamentally new principles are needed to understand how current flows at these nanometer length scales, traditional macroscopic concepts like mobility and diffusion coefficient need to be replaced by more basic concepts that require an understanding of resistance, friction, and electron transport at their most fundamental level. Regardless of the specific form future electronic devices adopt, it is clear that we need to develop ways to describe and model the electronic properties of device structures engineered on an atomic scale.