How much can you trust fingerprinting? How do insects help determine the time of a kill? How do they find political and war criminals using aging portraits? In this book, the world-famous Scottish writer and detective author Val McDiarmid changes roles and undertakes her own investigation. Its heroes are detective geniuses and ordinary police officers, great scientists and painstaking experts. High-profile cases that became the basis for movie plots, serial killers, victims of unhappy love or extreme sexual games, arsonists, molesters, scammers, marriage swindlers... And the search for truth. A long history of criminology unfolds before us - from the forensic medicine of Ancient China to DNA profiling - with her mistakes and victories, when after many years she manages to find the criminal and give freedom to the innocently convicted.