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