The second edition of "Neurons in Action" stimulates the student's learning with a detailed graphical insight into the nerve function that is just not possible to grasp in static textbooks. Students discover how changing parameters such as neuronal geometry, ion concentrations, ion channel densities, and degree of myelination affects the generation of action potentials, synaptic potentials, and the spread or propagation of voltages within a neuron. For instructors, minimovies of neuron simulations are provided for use in lectures.