The tutorial will present recent advances in methodologies for simulating the electrophysiology of cells and networks in the context of lower and higher scales or organization. At the lower scale, we will describe the simulation of intracellular chemical signals including calcium in subcellular compartments (dendrites and spines), with application to understanding of synaptic plasticity and the response of neuronal dynamics to modulators. At higher scales, we consider the brain as an organ, situating neurons in a complex environment of modulators, ions, and metabolism. The NEURON simulator will be used to illustrate the interactions among these levels, using NEURON's rxd reaction-diffusion module for intracellular and extracellular chemophysiology, and NetPyNE (www.netpyne.org) for managing parameters and for building complex networks of detailed cells as brain structures. We will also introduce new graphical methods (GUIs) for managing these extremely complex simulations. For more information see http://www.cnsorg.org/cns-2018-tutorials#T2.