John Lentini’s new book is ostensibly about arson cases. In truth, it is about something far larger: the habits of mind by which criminal justice systems turn uncertainty into guilt.

John Lentini’s new book, Twice Burned: A Fire Scientist’s Adventures in Overturning and Preventing Wrongful Arson Convictions, is far more than a specialist’s account of fire investigation. It is an important book about professional error, cognitive bias, institutional overconfidence, and the terrible human cost of wrongful conviction.

Lentini is no marginal technician in a narrow field. He is one of the central figures in the modern development of fire investigation in the United States. Over decades, he worked in laboratories, at fire scenes, in courtrooms, and within the bodies that shaped professional standards. He helped challenge myths long treated as settled knowledge, exposed the role of bad science in wrongful convictions, and pushed his field toward something both more modest and more rigorous: the scientific method.

That is precisely what gives the book its broader significance. Lentini does not merely narrate dramatic cases. He exposes the logic that produces failure. He shows how investigators become attached too quickly to a theory; how inconvenient facts are pushed aside; how hypotheses harden into certainties; and how entire systems gradually join the same mistake. Though the book’s raw material is American arson litigation, its lesson extends far beyond arson. It is a book about law, evidence, humility, and the danger of false certainty.

One of the most important concepts associated with Lentini’s work is negative corpus. The idea is simple, and devastating. Instead of proving what happened, the investigator concludes that the incriminating explanation must be correct because no satisfactory alternative explanation has been found. Guilt is not established by evidence; it is inferred from the absence of another story.

This must be distinguished from careful reasoning by elimination. Serious investigation often does exclude possibilities. But negative corpus is not disciplined exclusion within a broader evidentiary structure. It is the point at which the absence of an alternative ceases to signal the need for more inquiry and begins to function as evidence against the suspect. Instead of saying, “We do not yet know enough,” the system says, “If we have no other explanation, then this must be the one.” That is a dangerous move from evidentiary absence to positive conclusion.

At first glance, this may seem like a problem peculiar to fire scenes. It is not. It is a broader pattern of criminal reasoning, one that recurs wherever suspicion outruns proof. That is why Lentini’s book matters far beyond the world of arson. It gives us an exact vocabulary for a failure of thought that appears in homicide cases, sexual offense prosecutions, false confessions, and any criminal proceeding in which an institution finds uncertainty difficult to tolerate.

This is where the question of safety in criminal justice becomes crucial. In aviation, medicine, transport, and industry, it is long understood that error is not merely a personal failure. It is also the product of poorly designed........

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