How much can you trust fingerprinting? How do insects help determine the time of a murder? How do investigators find political and military criminals from portraits made with due allowance for aging? In this book, the world-famous Scottish writer and detective author Val McDermid switches roles and conducts her own investigation. Her characters are both crime-detecting geniuses and ordinary police officers, great scientists and meticulous experts. High-profile cases that became the basis for film plots, serial killers, victims of unfortunate love or extreme sexual games, arsonists, abusers, scammers, marriage swindlers… And the search for the truth. A long history of forensics unfolds before us—from forensic medicine of Ancient China to DNA profiling—with its mistakes and victories, when after many years it finally becomes possible to find the criminal and set free an innocent person convicted without guilt.