The report describes in a historical context the experiments that have been performed to examine the biological responses caused by exposure to low frequency electromagnetic radiation directly or as modulation of RF carrier waves. A detailed review is provided of the independently-replicated fundamental finding, the field enhanced efflux of calcium ions from brain tissue in vitro, as well as reports of CNS-related changes caused in synaptosome preparations, neuroblastoma cell cultures and intact whole animals. Studies performed with non-CNS tissue that have shown positive results caused by exposure to these electromagnetic fields are also reviewed. They include work with pancreatic tissue slices and lymphocytes. Recent results demonstrating the influence of the earth's magnetic field are also discussed, along with their implications for the design of future experiments. Lastly, the mechanism of action is conceptionalized, and recommendations are made to assist in attempts to correlate the results obtained with diverse biological systems.