The novel “Unfinished Solitaire” is based on the story of the investigation into a high-profile double murder committed in April 1888 in St. Petersburg. One of the victims of this crime was the sister of the famous ethnographer and traveler N. N. Miklouho-Maclay, who died by a strange coincidence a few days earlier (in the novel she appears under the surname Barclay). In 2006, an abridged version of the novel was published by the Krylov publishing house. This publication is the author's version of the text.