Ackerman, a professor at Yale Law School, and Hassler, a recent graduate, offer a readable but flawed brief against a section of the Clean Air Act, due for reauthorization this year. They begin with a case study of the 1977 amendments to the Act, which require scrubbers--to remove sulfur oxides from emissions--on all new coal-fired powerplants. Scrubbers, they point out, are just one way to control emissions--others are washing the coal and burning low-sulfur coal. And scrubbers are expensive; they break down; their performance is impossible to monitor. Because of requiring scrubbers, we may even get dirtier air: old, heavily polluting plants aren't required to scrub, and utilities may keep them in operation to avoid the extra cost of building a new plant with scrubbers. This messy problem, according to the authors, comes from Congressional meddling in the affairs of the Environmental Agency (EPA). Ignoring American experience with agencies left to their own devices (i.e., they tend to work for those they regulate), Ackerman and Hassler argue that an untrammeled EPA might have taken their preferred route: setting overall air standards, leaving to industry the strategy for compliance. Ignoring, too, the political lessons (for Congress) of that experience, the authors criticize the choice--prompted by a coalition of environmentalists and high-sulfur coal producers--of a particular, costly, solution. And a superficially appealing conclusion is offered--Congress should junk its expensive solution and give the EPA more discretion--without considering the argument that a solution of high economic cost may produce social benefits that outweigh those costs. Professor Ackerman's book will be read this year by Congress; his reputation assures that. It should be read skeptically.