If governments hope to slow global warming and rising sea levels, they must reduce the emission of greenhouse gases, especially carbon dioxide. Metcalf, an economist and former U.S. Treasury official, argues that the best way to do that is to levy a tax on carbon emissions. Such a tax would be far superior, in his view, to both strenuous new regulations on carbon emissions (although some additional regulations will be needed) and cap and trade, a program in which companies are given emission allowances and permitted to sell what they do not use to companies that exceed their limits. Any new tax produces distributional concerns. Metcalf would prefer to return the substantial revenues generated by a carbon tax to the tax-paying public, perhaps by reducing other taxes. The book doubles as a primer on public taxation. Metcalf draws the majority of his examples from the United States, but his argument applies to most other countries, as well.