This is the first volume of the four-volume edition on thermoelectricity.The author of the book is Lukyan Ivanovych Anatychuk, a well-known scientist in thermoelectricity, Doctor of Science, academician of the National Academy of Sciences of Ukraine, President of the International Thermoelectric Academy. The book presents state-of-the art phenomenological theory of thermoelectricity, microscopic theory of thermoelectricity and theory of thermoelectric power conversion. The book is comprised of 5 chapters: The phenomenological theory of thermoelectric effects, The microscopic description of thermoelectric effects, Eddy thermoelectric currents, Thermoelectric power conversion, and Thermoelectric conversion of information. The information presented in this book contributes to statement of new investigations in thermoelectricity eventually extending the possibilities of practical application of thermoelectricity. The book may be useful for investigators in thermoelectricity, designers of thermoelectric equipment, physicists of various trends, postgraduates and students, persons willing to get acquainted with thermoelectricity.