The story “The Secret of the Oprichnik” opens an adventure series of historical detective stories written by the author. It tells about the search for treasures hidden in a hiding place under Ivan the Terrible, as well as about the true events of that time: about the case of Solomonia Saburova, about the causes of the Novgorod pogrom, about the search for the Amber Room, stolen during the Second World War. The story “Crime in Sloboda” lifts the veil of secrecy over the investigation into the circumstances of the death of Tsarevich Ivan. Boris Sudarushkin enriched the detective story with fascinating historical content, using all the expressive possibilities of historical prose, which is not alien to the action, romance of collisions and characters.