Introduction -- Part I: Electricity Within Humans -- Basic Unit of Human Electricity -- Electric Potential at Rest -- Electrical Potential at Action -- Receptor Potentials -- Conduction and Control of Electrical Potentials -- Part II: Electricity From Humans -- Electrical Signal From the Heart -- Electrical Signal From the Brain -- Electrical Signals From Other Muscles and Neurons -- Brain-Computer Interface -- Electrical Signals for Human Identification and Authentication -- Part III: Electricity Toward Humans -- Electrical Stimulation for the Heart -- Electrical Stimulation for the Brain -- Electrical Stimulation for the Hearing and Vision Disabled -- Electrical Stimulation of Nerves and Muscles -- Health-Related Effects of Electricity.