Anatoly Dnieprov (born 1919), the author of Siema, which he wrote in 1958, is a distinguished physicist who works at an institute of the U.S.S.R. Academy of Sciences. His first book appeared in 1946. His favorite subject is cybernetics - its amazing achievements to date and its breathtaking potentialities. Scientific authenticity is a salient feature of his writings.

Victor Separin (born 1905), a journalist by profession, is editor of the Soviet popular geographic magazine Around the World. His fiction, which treats of present-day scientific and technical problems, is amazingly realistic. In this volume he is represented by The Trial of Tantalus, a story dealing with prospects of microbiology.

Arkady and Boris Strugatsky, authors of The Six Matches, are frequent contributors to Soviet popular science periodicals. Few readers know, however, that the two brothers are not professional writers. Boris Strugatsky (born 1933) is an astronomer and works at the computer laboratory of Pulknovo Observatory. Arkady (born 1925) is a linguist and translator specializing in Japanese.

Valentina Zhuravleva (born 1933) is a comparatively recent graduate of the Azerbaijan Medical Institute. She was probably prompted to try her hand at scientific fiction by the almost fantastic possibilities offering in the field of medicine. The bold flights of fancy in her scientific thinking make her stories particularly noteworthy. Bio-automation is the theme of her Stone from the Stars, written in 1959, and included in this volume.