The Razor's Edge is one of the cult novels of its era. Italian adventurers in search of diamonds in Africa, a Soviet scientist exploring the hidden capabilities of the human brain, an Indian artist - the fates of these completely different people are united by the secret of the black crown, which played an important role in the life of Alexander the Great. "Starships". Soviet paleontologists discovered the remains of dinosaurs with wounds from an unknown weapon. Comparing their discovery with a recent hypothesis by astronomers, scientists came to the conclusion that aliens once visited the Earth. “Nur-i-Dasht Observatory” and “Lake of Mountain Spirits” are famous stories from the writer’s early cycles. Ivan Efremov is a classic of Soviet science fiction.