Serial killers are hunters, and their prey is human. They seek, stalk, and slay their victim, then start looking for another. Over the past twenty-five years, serial killers—both real and fictional—have assumed a major role in America's nightmares.

David Berkowitz, the notorious serial killer known as "Son of Sam," is transported after his arrest in 1977. AP/Wide World Photos. Reproduced by permission.

Although this crime is hardly a modern invention, the term "serial killer" was coined by Federal Bureau of Investigation (FBI) agents in the early 1970s. Criminologists distinguish between the "mass murderer" and the "serial killer." The mass murderer kills a number of victims at once, as part of a single explosion of rage; the serial killer, however, spreads out his butchery over time and territory.

The first serial killer to attract wide popular attention was probably Jack the Ripper, who murdered five...