Many theories--from the routine to the bizarre--have been offered up to explain the crime decline of the 1990s. Was it record levels of imprisonment? An abatement of the crack cocaine epidemic? More police using better tactics? Or even the effects of legalized abortion? And what can we expect from crime rates in the future? Franklin E. Zimring here takes on the experts, and counters with the first in-depth portrait of the decline and its true significance...