Just as our transportation system, like most complex systems, has grown ever more sophisticated, so have the means of investigating when those systems suffer failures. For years, a pronouncement of "human error" signaled the end of an accident investigation; now it often marks the beginning. It is no longer sufficient to conclude that an error occurred; investigators must now determine why it occurred and what can be done to prevent a recurrence. Yet surprisingly, there has been little in the training canon to prepare the accident investigator for this central function. That is, until now, because Dr. Barry Strauch has masterfully filled that gap. "Investigating Human Error: Incidents, Accidents, and Complex Systems" is that rarity in the literature of any discipline: a text that is thorough, well-organized and also a pleasure to read. Strauch is clearly at home in both the academic world and the gritty, high-stress environment that surrounds the investigator in the field. Each page of his book is informed by his years of experience as an investigator, an educator and a human factors psychologist. With the systematic, insightful approach presented by Strauch, complex systems are no longer impenetrable to the investigator; human error ceases to be a conundrum. Furthermore, Strauch's audience extends well beyond the ranks of investigators alone. His book will be profoundly appreciated by the people who work in airlines and other complex systems, by those who manage them and by those who analyze and regulate them. In fact, Strauch's work will be a compelling read for anyone who is fascinated and perplexed by humans failing to perform as they should in critical missions.