Edward Oscar Heinrich was known as the American Sherlock Holmes, not only because he cracked over 2,000 cases in his 40-year career, but because of the way he did it. Heinrich was, in the 1930s, one of the first forensic scientists in the country. He was an expert witness who pioneered the use of blood-spatter analysis and fingerprints as evidence. The author, a journalism professor and host of popular true crime podcasts, introduces readers to this amazing detective whose triumphs—and failures—changed the world of crime forever.