Steven Landsburg's writings are living proof that economics need not be "the dismal science." Readers of The Armchair Economist and his columns in Slate magazine know that he can make economics not only fun but fascinating, as he searches for the reasons behind the odd facts we face in our daily lives. In More Sex Is Safer Sex, he brings his witty and razor-sharp analysis to the many ways that our individually rational decisions can combine into some truly weird collective results -- and he proposes hilarious and serious ways to fix just about everything.

When you stand up at the ballpark in order to see better, you make a rational decision. When everyone else does it too, the results, of course, are lousy. But this is just the tip of the iceberg of individual sanity and collective madness. Did you know that some people may actually increase the spread of sexually transmitted diseases when they avoid casual sex? Do you know why tall people earn more money than shorter competitors? (Hint: it isn't just unfair, unconscious prejudice.) Do you know why it makes no sense for you to give charitable donations to more than one organization?

Landsburg's solutions to the many ways that modern life is unfair or inefficient are both jaw-dropping and maddeningly defensible. We should encourage people to cut in line at water fountains on hot days. We should let firefighters keep any property they rescue from burning houses. We should encourage more people to act like Scrooge, because misers are just as generous as philanthropists.

Best of all are Landsburg's commonsense solutions to the political problems that plague our democracy. We should charge penalties to jurors if they convict a felon who is later exonerated. We should let everyone vote in two congressional districts: their own, and any other one of their choice. While we're at it, we should redraw the districts according to the alphabetical lists of all voters, rather than by geography. We should pay FDA commissioners with shares of pharmaceutical company stocks, and pay our president with a diversified portfolio of real estate from across the country.

Why do parents of sons stay married more often than parents who have only daughters? Why does early motherhood not only correlate with lower income, but actually cause it? Why do we execute murderers but not the authors of vicious computer viruses? The lesson of this fascinating, fun, and endlessly provocative book is twofold: many apparently very odd behaviors have logical explanations, and many apparently logical behaviors make no sense whatsoever.