Metals are ubiquitous and play a critical role in neurobiology. Transition metals are important because they alter the redox state of the physical environment. Biologically, transition metals catalyze redox reactions that are critical to cellular respiration, chemical detoxification, metabolism, and even neurotransmitter synthesis. Many metals are both nutrients and neurotoxicants, such as iron, zinc, copper, and manganese. Other metals, such as lead and cadmium, are metabolized similarly to these metals, particularly iron. Iron metabolism and genes that regulate iron metabolism may be the key to understanding metal toxicity. Finally, recent evidence demonstrates that early life exposures may program later life and adult disease phenotypes via processes of epigenetics. Parallel work in metals demonstrates that epigenetics may be a critical pathway by which metals produce health effects.