The best time-travel story since H.G. Wells's The Time Machine, by the Grand Master of science fiction, the story of Andrew Harlan, Technician and Eternal.
'Isaac Asimov was one of the great explainers of the age...It will never be known how many practicing scientists today, in how many countries, owe their initial inspiration to a book, article, or short story by Isaac Asimov'
Carl Sagan
'Asimov displayed one of the most dynamic imaginations in science fiction'
Daily Telegraph
'Asimov's career was one of the most formidable in science fiction'
The Times