Not all failures have the same causes. The book uses seven broad patterns to help readers tell them apart.

Exploratory Failure — A reasonable attempt does not produce the expected result, but leaves behind useful evidence and new clues.

Information-Limited Failure — People make decisions based on what could reasonably be known at the time, only to discover important facts later.

Testing Failure — A theory, product, or system is not challenged under conditions realistic enough to reveal its weaknesses.

System Failure — Several small weaknesses interact and create an outcome that none of them could have caused alone.

Leadership Failure — People with decision-making power ignore evidence, suppress disagreement, or allow schedule, cost, or reputation to outweigh risk.

Ethical Failure — Human beings are treated as means to an end rather than as people with rights who deserve protection.

Adaptation Failure — An organization depends so heavily on the system that created its past success that it struggles to change when the world around it does.

These categories are tools, not verdicts. Many important failures fit more than one pattern.

They help us ask a more important set of questions:

What could not have been known—and what should have been known? What was genuine exploration—and what was an existing warning that was ignored?