Study of the biological effect of magnetic fields is both a very old and a very recent area of investigation. A connection between health and the mysterious force of the lodestone has been suspected since the dawn of human culture. Nevertheless, only during the last decades has reliable evidence of biological effects of the magnetic field been dis­ covered. The purpose of this book is to bring together in one volume the present-day knowledge in all the active fields of biomagnetic research and at the same time to provide a theoretical and practical background to all scientists who wish to engage in investigations in this new disci­ pline. The need for such a comprehensive survey of current informa­ tion became evident to the editor from the interest manifested in the biomagnetic symposia and from the extended correspondence maintained by the Biomagnetic Research Foundation. It is hoped that the book will aid in attracting the interest of specialists and may thus serve as a catalyst for interdisciplinary exchange of ideas.