The objective of this study is analysis of the clinical efficacy of picotesla magnetic fields in the treatment of epilepsy, Parkinson's disease and multiple sclerosis. The method utilized involved the exogenous application of physiologic, very weak magnetic fields to the brain by Sandyk, Anninos, Derpapas and Tsagas. The magnetic device produced a magnetic field ranging from about 5 x 10(-8) gauss to about 2.5 x 10(-7) gauss at frequencies of 2 to 7 Hertz. The wave form was sinusoidal and the device was positioned about the posterior portion of the corpus callosum most specifically to influence the pineal gland. Direct correlation of melatonin production with magnetic field stimulation was established. Amelioration or palliation of the neurological conditions was observed over an extended period of time in most cases. It appeared that a resonance situation was established between the magnetic field and melatonin which could be explained with Jacobson Resonance. These studies begin to point to the explanation of the mechanism of interaction between non-ionizing electromagnetic radiation and biological systems. Furthermore, the evaluation of the pineal gland as an magneto-sensitive gland may help us understand fundamental conditions in magneto-receptors of biological systems in terms of their piezoelectric nature.