At the International Congress of Criminologists held in Switzerland in 1913, the Moscow Detective Police was recognized as the best in the world in solving crimes. And it was led by “the most important detective in Russia,” the head of the entire criminal investigation department of the Russian Empire, Arkady Frantsevich Koshko (1867-1928). His memoirs, published in Paris at the end of the 20s, paint a detailed picture of the confrontation between the pre-revolutionary police world and the criminal world. On the pages of the book, the reader will meet brave detectives and fanatical criminals, investigator-psychologists and noble “Warsaw thieves.”