Electromagnetism is basic to our understanding of the properties of matter and yet is often regarded as a difficult part of an under- graduate physics course. In this book answers are developed from first principles to such questions as: What is electricity? What is electromagnetism? Why are some materials magnetic and others non-magnetic? What is magnetism? Physics answers these questions in two related ways. On the one hand the classical explanation is in terms of classical concepts: electric charge q, electric and magnetic fields (E and B) and electric currents. On the other hand the...