Accumulating evidence suggests that MeHg sequesters the trace element selenium in the body, thus preventing it from performing its essential physiological roles. This new book describes reasons why the risks of adverse effects of MeHg exposure are outweighed by the benefits of one to two servings of fish per week. Since unnecessary avoidance of fish consumption could result in significantly higher coronary disease deaths and sub-optimal neural development in children, consideration of mercury-selenium interactions may assist regulatory agencies in their efforts to protect and improve public health.