True crime books are not usually read for their intellectual heft. People look to them for sensation rather than deep thoughts. Two new books, however, not only combine crime and intellectual heft, they do it in such unexpected ways they could well become classics of the genre. Distinctive classics, too: One of the authors is a cerebral, apparently stable university researcher; the other is a disgraced journalist.

A Hard-Wired Impulse

In The Murderer Next Door: Why the Mind Is Designed to Kill (Penguin Press, $24.95), David M. Buss applies evolutionary theory to explain modern murder. A University of Texas psychology professor, he became drawn to the gruesome project, he writes, after witnessing a friend "fly into a murderous rage one night at a cocktail party." Until that night, Buss believed his friend to be a peaceful man in a happy marriage. So why did he suddenly seem capable of killing his wife?

Buss found himself questioning his belief that "only crazy or desperate people . . . or people brought up in subcultures of violence that have desensitized them" think about committing murder. As he studied the research of others and launched seven years of his own investigations, he developed a view of homicide as a survival strategy hard-wired into the human mind. It had little, if anything, he concluded, to do with the usual contemporary villains -- media violence, pornography, drugs, poverty. Societies predating television, meth epidemics and urban ghettos experienced murder rates equal to or exceeding today's.

Buss's meticulously designed and controlled research studies began informally when he asked students to complete a questionnaire that included the inquiry "Have you ever thought about killing someone?" The replies astonished him.

"Nothing had prepared me for the outpouring of murderous thoughts my students reported," Buss says. "These were intelligent, well-scrubbed, mostly middle-class kids, not the gang members or troubled runaways one might expect to express violent rage. Yet most of them had experienced at least one intense episode in which they had fantasized about killing someone."

Buss launched a study of homicidal fantasies in more than 5,000 people around the globe. His findings suggested that about 91 percent of men and about 84 percent of women, across cultures, think at some point about murdering a specific person; some act on those thoughts. Using his own data and supplementing it with a synthesis of others' research, Buss developed a theory encompassing murders from crimes of passion to premeditated contract killings.

Murder "can be explained by the twists and turns of a harsh evolutionary logic," he writes. "Killing is surely ruthless, but it is also most often not the result of either psychosis or cultural conditioning. Murder is a product of the evolutionary pressures our species confronted and adapted to."

In fact, Buss argues, murder has been so constant in nearly every society for thousands of years -- and so beneficial to human evolution -- that "the real mystery is . . . why killing has not been more prevalent." He suggests an answer to that mystery, as well: "The evolution of the psychology of murder has been like an arms race: in response to the threat of murder, we've developed a well-honed set of defenses against it, and they have acted as powerful deterrents."

As Buss unveils the subtleties of his theory -- debunking traditional explanations for domestic violence, for example -- his contravening of the conventional wisdom on murder shows promise of becoming the new conventional wisdom.

Shades of Truth

Michael Finkel's True Story (HarperCollins, $25.95) -- an unusual but effective amalgam of murder investigation, memoir and media criticism -- focuses on two men rather than all humanity.

One is a murderer-next-door in the Buss mold: Christian Longo, a seemingly pleasant, accomplished man accused of killing his wife and three young children in small-town Oregon. The other is Finkel himself, a contributor of hard-edged features to the New York Times Sunday magazine who was caught fabricating a character while reporting from the African nation of Ivory Coast.

Fired and disgraced, Finkel was about to isolate himself in his Bozeman, Mont., home when he received a surprise call from a reporter at the Oregonian newspaper in Portland. Finkel steeled himself for questions about the end of his career. But the reporter knew nothing about that. He wanted to interview Finkel about Longo, the murder suspect, who had fled to Mexico and adopted Finkel's identity as a disguise.

With time on his hands, Finkel decided to contact Longo in jail, where the murder suspect was awaiting trial. In fact, Finkel was the only journalist Longo would talk to. A bizarre correspondence ensued between the lifelong sociopath and the troubled journalist, leading the latter to question the nature of Truth -- in the criminal justice system, in journalism, in every human mind and heart. Looking into the homicides, Finkel believed Longo had murdered his entire family. But no matter how often he thought through the different versions offered by Longo, the details of the crime remained elusive.

Reading the accurately yet ironically titled True Story is rather like watching a train wreck. There is nothing pleasant about it, but there is no turning away.

Agent on a Harley

Reviewers tend to ignore the type of book William Queen has written. Why? Because the undercover-cop-brings-down-the-bad-guys genre is often published only in the form of cheap airport paperbacks, which, for better or worse, Sunday book sections studiously avoid.

The protagonists of Queen's memoir, Under and Alone (Random House, $24.95), are the antithesis of Buss's Everyman murderers. Rather, they are portrayed as evil incarnate. The subtitle, The True Story of the Undercover Agent Who Infiltrated America's Most Violent Outlaw Motorcycle Gang, might lead those with casual knowledge of motorcycle gangs to think Hell's Angels. Wrong. The gang that Queen infiltrated in 1998 as an agent of the U.S. Treasury's Bureau of Alcohol, Tobacco and Firearms was the Mongols. Set mostly in California, Queen's saga covers about two years. A middle-aged Vietnam veteran turned law-enforcement officer posing as a Mongols prospect, Queen was so convincing as Billy St. John that, despite many occasions in which he thought he had been outed and confidently expected to be killed, he became a full Mongols member. As such, he witnessed or heard about numerous crimes, including murder, rape, drug dealing, drug use, theft and extortion. Each time, he had to decide whether he could do anything to halt the illegal activity without blowing his cover. His decision-making was complicated by the humanity he glimpsed in some of the Mongols members from time to time.

Besides Queen and the thugs he hung out with, characters in the book include ATF agents with the thankless task of serving as Queen's backup, plus the author's endangered, long-suffering wife and sons.

The threat to Queen was so huge that the book is both frightening and exhausting on almost every page. Could it all be true? How did the publisher verify the often hard-to-believe information? That is not explained. One thing is beyond doubt, however: The arrests stemming from Queen's information led to 53 convictions.

A Bludgeoning in Old Iowa

Midnight Assassin: A Murder in America's Heartland, by Patricia L. Bryan and Thomas Wolf (Algonquin, $23.95), continues the murderer-next-door theme, with a variation: The most likely suspect is a woman. Set in rural Warren County, Iowa, during the first decade of the 20th century, this real-life mystery succeeds on many levels.

Bryan, a law professor, and Wolf, her husband and a professional writer, lived in Iowa before settling in Chapel Hill, N.C. Bryan became fascinated with the December 1900 murder of a prosperous farmer, John Hossack, but by an indirect route. Bryan is a scholar of the writings of Susan Glaspell, the feminist and author who as a young woman covered the Hossack murder for a Des Moines newspaper.

Margaret Hossack, a farm wife and the mother of nine children, never denied she was sharing her husband's bed when somebody killed him with an ax as he slept. She had told neighbors for at least 15 years that John sometimes abused her, although she denied the abuse to the authorities. Was it possible that she slept through the murder, just inches from her husband, and that the killer spared her? Was she protecting one of her children? A jury convicted Margaret, an appellate court overturned the conviction, and a second jury could not reach a verdict. She spent the final years of her life as a widow living in freedom.

Bryan and Wolf cover the murder investigation and the trials thoroughly and gracefully. Better still, they place the crime in the context of the times, before feminism had won widespread acceptance. No feminist herself, Margaret Hossack either murdered her husband in accord with evolutionary reasons posited by Buss, the psychology professor, or suffered through two trials because somebody else had his own evolutionary reasons for taking John Hossack's life. *

Steve Weinberg lives in Columbia, Mo., and is a director of the National Book Critics Circle.

William Queen (wearing bandana at right) with members of the outlaw motorcycle gang the Mongols