Leyton is an anthropologist, and this study of serial killers focuses on sociocultural factors rather than individual pathology as a cause of multiple murder. Specifically, Leyton examines how class conflict has contributed to serial killings in different epochs. In the Middle Ages, royalty killed serfs; in the Industrial Age of the 19th century, the nouveau middle class killed prostitutes and other individuals from the lower rungs, and in the modern era serial killers target those who are just one rung up from them in the social ladder.
Leyton argues that modern multiple murderers are class-conscious and socially conservative men who are obsessed with status, class, and power. Emboldened by our cultural glorification of violence and serial killers, and trapped in alienating lives that do not match their class strivings, they kill the objects of their desire. And they keep killing until they feel that they have accomplished the mission that they set out on. It's a very interesting analysis, although I think Leyton selected case studies that fit his thesis and ignored others that did not. (He profiles Ted Bundy, Edmund Kemper, David Berkowitz, and four other cases, including the D.C. snipers in his new edition, but he ignores - for example - Jeffrey Dahmer, whose predilection for young Cambodian boys goes against his thesis.) Also, the fact that documented serial killers in the Middle Ages were royalty may be due to documentation issues; maybe serfs who killed serfs never made the history books (a possibility Leyton doesn't mention).
But these are minor limitations. The book is well researched and well written, and it is certainly refreshing to see a treatment of this topic that does not ignore the macro perspective of class, race, and culture. In my own forensic psychology practice, I have found it helpful to keep Leyton's perspective in mind, while still not ignoring the developmental wrong-turns and individual pathologies that also contribute to multiple murder. Overall, this book is well worth reading for anyone interested in the etiology of serial murder.