There is much to be learned from Frank Zimring’s highly readable and penetrating examination of the U.S drop in crime in the 1990s. Zimring does a masterful job of illustrating how when crime was rising in the 1970s the message that nothing can effectively prevent it was widely accepted. Skip ahead to the period following the 1990s crime drop and every policy from more and better policing to greater reliance on incarceration to more gun control – or even more guns – has some champion for the view that they are particularly effective crime fighters. As is often the case, the public commentary tends to be simplistic and misleading, but my own view is that the rough contours of why crime fell are clearer than Zimring believes.