In the past, the authors maintain, investors did not know how to pick truly good (that is, moral) companies, but it turns out that it's beguilingly simple: Shares of companies whose managers lean Democratic have far outperformed the shares of companies with G.O.P.-leaning managers. Starbucks has beaten Exxon. Apple has trumped Dell. Forest Laboratories has run laps around Pfizer. You get the picture.

Adamson and Andrew, who are passionate Democrats, take their party's moral superiority as a given. (The second half of the book, oddly unrelated to the first, is a call to arms for retaking the White House that they have named "The Blue Manifesto.") That Democratic-leaning companies purportedly outperformed their competition is offered as proof that morality pays—that progressive values are better "not only for employees, the environment, and our country but for investors and for a company's financial bottom line."

The evidence for this statement, and really for the book's entire argument, comes from the authors' unique analysis of how stocks in Standard & Poor's 500-stock index performed. Previous devotees of socially responsible investing distinguished corporations on the basis of their behavior—whether or not they were eco-conscious, cooperative with unions, and so forth. But Adamson and Andrew also focus on the political contributions of executives and corporate PACs. They separate companies according to which party received the majority of the company's dollars, which yields 80 Democratic-leaning firms from the S&P 500.

They further prune their list of companies whose unsaintly deeds violate progressive values, leaving a "blue index" of 76 firms. The performance—at least the performance they report—was phenomenal. A hundred dollars invested in the blue index on May 30, 1997, would have grown in 10 years to $1,963, nearly a twentyfold gain. By comparison, the same amount invested in stocks of Republican-leaning firms over the same period would have yielded only $322.

What's more, Adamson and Andrew assert, investing in blue stocks will improve the world. But this seems far-fetched. When you invest in Microsoft, the money does not go directly to Bill Gates' political causes, nor does an investment in Dell find its way to Karl Rove. (For another perspective on socially responsible investing, see "No Obligations," by Robert B. Reich.) Moreover, the dollars involved are trivial: Political contributions from S&P 500 corporations have averaged less than $1 million per company over the past decade. The donations seem too small to encourage any meaningful and lasting shifts in government policy.