"We - Nikolay Свечин, Valery Введенский and Ivan Погонин, is authors of historical detectives. Our literary heroes investigate crimes in the Russian empire in the end XIX - beginning of the XX century. And although on historical measurements since passed not too plenty of time, huge changes happened in life and way of life of people, their psychology, behavior and presentations. And to describe a that epoch, not blushing then before knowing people, we, before what to sit down for a next story or novel, we study sources: memoirs and diaries, newspapers and magazines, reference books and reports, advanced studies of those years and fiction, archived documents. However far not all information known to us can be "packed" in the format of fiction work. Therefore for the time being the great number of interesting facts remained in our notebooks. And then an idea to write this book appeared: to tell oh histories of the Petersburg of criminal investigation police, about that, how searched in former times of criminals in the capital, about the fates of tsar's detectives and businesses" exposed by them.