Although much of circuit theory can be taught without explicit reference to the electromagnetic fields that exist in and around real circuits, a point is always reached at which ignorance of certain basic properties of electromagnetic fields hinders further progress. This text aims to provide a firm foundation in this area for first and second year students, and to provide additional knowledge of electromagnetism necessary for the understanding of the operation of many other aspects of electronic systems in general, such as sensors, distributed elements and systems, telecommunications, radar, solid state devices/integrated circuits, opto-electronic systems and the increasingly important topic of electromagnetic compatibility. The emphasis is on the practical; indication is given where mathematical passages can be skipped: results are highlighted. Examples and practical methods of simplifying analyses are given.