This book contains information about the theory of electromagnetic fields in conducting mediums. It describes the theoretical foundation of electromagnetic methods used in all areas of exploration geophysics, including a study of the earth's deep layers. This book will be useful for research and exploration geophysicists, electronic engineers, and graduate and undergraduate students in university geophysics departments.. Electromagnetic fields in conducting media. Physical principles of electromagnetic methods applied in geophysics. Relationship between electromagnetic fields and parameters of a medium