The film script “Eclipse Day” based on the story “A Billion Years Before the End of the World” was written by the Strugatskys (in fact, by Boris Strugatsky alone) in collaboration with P. Kadochnikov in 1981. First magazine publication: “Knowledge is power”, 1987, Nos. 5–8 (this is the only publication in which P. Kadochnikov is listed as one of the authors); first book: “Five spoons of elixir.” M., “Science”, 1990. The original version of the script was written by P. Kadochnikov based on materials and sketches provided by B. Strugatsky, first published in the series “Unknown Strugatskys”. Subsequently, at the request of director A. Sokurov, the script was significantly revised, more precisely , completely rewritten by Yu. Arabov. Based on this scenario, in 1988 Sokurov made the film “Days of Eclipse.”