"Kosen" is an exciting science fiction book written by Ukrainian writer Oleksandr Zorich. This novel tells the story of a mysterious extraterrestrial object that landed on Earth. The main character, a young cryptographic scientist, decides to reveal the secret of the miracle device with the help of ciphers and codes, which leads to incredible discoveries. The author skilfully combines scientific facts with fantastic elements, which creates an unparalleled atmosphere and intrigues the reader. "Kosen" is a book that fascinates with its mystery and opens new horizons in the world of science and fantasy.