Biomagnetism involves the investigation of bioelectric processes as reflected by their accompanying magnetic fields. These processes can be monitored in the brain, heart, peripheral nerve or gastrointestinal tract. SQUID technology can also be used for biosusceptometry in lung, liver and intestines. Biomagnetism also includes theoretical issues as encountered in the inverse problem, modelling, fundamentals, physics and mathematics of the method, technical applications and instrumentation, as well as future aspects. The topics of this book reflect the issues of fundamental research in biomagnetism, such as modelling and instrumentation, as well as the application of biomagnetism in clinical neurology, brain physiology, cardiology, peripheral nervous system, gastroenterology, biosusceptometry and animal research.