Val McDermid portrays forensic scientists as dedicated and smart, while ignoring scandals in the field. (Alexandra Garcia/The Washington Post)

Douglas Starr is co-director of the graduate program in science journalism at Boston University. His most recent book is “The Killer of Little Shepherds: A True Crime Story and the Birth of Forensic Science.”

What Bugs, Burns, Prints, DNA, and More Tell Us About Crime

By Val McDermid

Grove. 310 pp. $26

Val McDermid is one of the most popular crime-fiction writers today. Her 27 novels have sold 11 million copies worldwide, according to her Web site, and have won several crime-fiction awards. Now she has written a nonfiction book about criminal forensics as a kind of paean to all those experts whose work has informed hers over the years. “The stories these scientists have to tell us . . . are among the most fascinating you will ever hear,” she declares, and she tells plenty of them.

McDermid organizes the book into 12 chapters, each of which represents a different aspect of crime-scene investigation. Much as an investigator would, she starts by approaching the crime scene itself, discussing how it’s cordoned off, who takes charge, the CSI’s position in the chain of command and how the scientist works his or her way through the case. Frequently, she introduces us to an investigator who becomes our guide.

‘Forensics: What Bugs, Burns, Prints, DNA and More Tell Us About Crime’ by ValMcDermid (Grove)

Throughout the book, she portrays forensic scientists not as emotionless Sherlock Holmes types (although she evokes him repeatedly) but as human beings who care about what they do and are troubled by what they see. Along the way McDermid examines topics of forensic science such as pathology, toxicology and fingerprinting, fleshing out the historical and technical aspects, always telling vivid stories. We meet a collection of sympathetic characters, including fire investigator Niamh Nic Daeid, blood-spatter specialist Val Tomlinson, anthropologist Sue Black and several others, all of whom are bright and dedicated professionals. We also meet some not-so-nice characters — criminals past and present whom forensic specialists have helped to apprehend. And we hear about Buck Ruxton, who in 1935 murdered his wife and maid, mutilated their bodies (including cutting off their fingertips), and threw the parts in a stream. He was convicted based on two key pieces of forensic evidence: the identification of a species of maggot on the bodies, which narrowed the time frame, and a photographic reconstruction of the victims’ faces.

Such stories populate the book and make it quite readable, and McDermid’s deep dives into history and science add substance. She does a commendable job of explaining some timely issues, such as the use of mega-data in digital forensics and the latest controversies about forensic DNA.

Yet certain weaknesses prevent this from being the go-to book for those who wish to learn about forensics. The author has a tolerance for cliche: “Truth is stranger than fiction,” she tells us; a female fingerprint expert shows a “steely intelligence,” a CSI team “came to the rescue.” She concludes a smart section about how experts are beginning to question the validity of traditional fingerprint evidence by comparing it to a “greedy grandfather . . . unaware that the times they are a’changin.’ ”

Historical inaccuracies also pepper the book. At one point, McDermid says that in the late 19th century, Alfred Bertillon invented a system of biometric identification that was accurate to a factor of 1 in 286 million. Actually he claimed an accuracy of 1 in 4 million. She lists several “firsts” that really weren’t, such as her claim that Frenchman Edmond Locard opened the world’s first crime investigation laboratory in 1910. His professor, Alexandre Lacassagne, did that decades earlier.

This careless writing and fact-checking undermines the book’s credibility. Furthermore, after reading “Forensics” one could conclude that, despite the occasional problems and missteps, forensic science is basically healthy and that “the people who do it are, frankly, awesome.” Events of the past several years show otherwise, however.

In a widely cited 2009 report, the National Academy of Sciences portrayed forensic work as fundamentally flawed, saying that with the exception of DNA evidence, most forensic tools, such as hair comparison and blood-spatter analysis, are more like traditional beliefs that have never been statistically tested. One of the most troubling areas is arson investigation, which McDermid portrays uncritically in her book. Over the past couple of decades, research has revealed that many of the traditional signs of arson also routinely occur in accidental fires, and there have been an unknown number of wrongful convictions. Even a cursory news search about arson will turn up the case of Cameron Todd Willingham, who was executed in Texas for the deaths of his three daughters in what experts now believe was an accidental blaze. Similarly, scandals surrounding forensic laboratory personnel have been making headlines for years; take, for instance, Annie Dookhan in Massachusetts, whose fraudulent practices tainted tens of thousands of drug cases. In Britain, the findings of an explosives expert played a role in the false conviction of the Birmingham Six. Omitting these scandals and the lessons they convey gives a less-than-realistic portrayal of the field.

That’s not to say “Forensics” is less than an enjoyable read. It skips along from story to story, and readers who aren’t squeamish will be entertained and intrigued. It will certainly please readers of McDermid’s novels, who will want to have her take on the subject. But readers seeking an authoritative book on a rapidly emerging and controversial field should look elsewhere.