1
This article originally appeared in
Astounding Science Fiction, June
1953.
2
Indeed, he used it three more
times—Star Light written at the request of
John W. Campbell, “Lecture Demonstration” written at the request of
Harry Harrison for Astounding: The John W.
Campbell Memorial Anthology, and
“Under” written at the request of NESFA Press for this book but
first published in Analog, January 2000 as
the cover story of its 70th Anniversary issue.—Editors
3
This refers to Isaac Asimov’s novel
Pebble in the Sky.—Editors
4
Hello 1953, from 2000—we now know that the
superjovian planet in the 61 Cygni system is in orbit around 61
Cygni B.—Editors
5
This addendum, written in March 1999, first
appeared in print in Analog Science Fiction and
Fact, January 2000.
6
The author can no longer find this program, or
we would have included it as an appendix—Editors