A couple on a train wondering what might have happened if they had not met when they did, meet a fellow passenger who supplies an answer.
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| June 1952 |
|
Fantastic, Summer 1952 | Ziff-Davis Publishing Company | MAGAZINE | 106 |
| March 1953 |
|
Science-Fiction Adventures in Dimension | Vanguard Press | Anthology | 235 |
| 1955 |
|
Adventures in Dimension | Grayson & Grayson | Anthology | |
| January 1955 |
|
Häpna!, januari 1955 | Grafiska Förlaget Kindberg & Söner | MAGAZINE | |
| June 1962 |
|
Great Science Fiction by Scientists | Collier Books | Anthology | 17 |
| June 1962 |
|
Great Science Fiction by Scientists | Collier Books | Anthology | 17 |
| June 1962 |
|
Great Science Fiction by Scientists | Collier Books | Anthology | 17 |
| February 1964 |
|
Dodici volte domani | Casa Editrice La Tribuna | Collection | 329 |
| March 1965 |
|
Science Fiction Adventures in Dimension | Berkley Medallion | Anthology | 140 |
| 1966 | Great Science Fiction by Scientists | Collier Books | Anthology | 17 | |
| 1967 |
|
Great Science Fiction by Scientists | Collier Books | Anthology | 17 |
| 1968 |
|
Great Science Fiction by Scientists | Collier Books | Anthology | 17 |
| 1969 |
|
Nightfall and Other Stories | Doubleday | Collection | |08 |
| June 1969 |
|
Fantastic, June 1969 | Ultimate Publishing Co., Inc. | MAGAZINE | 129 |
| December 1969 |
|
Nightfall and Other Stories | Doubleday / SFBC | Collection | 191 |
| 1970 |
|
Great Science Fiction by Scientists | Collier Books | Anthology | 17 |
| 1970 |
|
Dodici volte domani | Casa Editrice La Tribuna | Collection | 329 |
| June 1970 |
|
Nightfall and Other Stories | Rapp & Whiting | Collection | |08 |
| July 1970 |
|
L'amour, vous connaissez ? | Denoël | Collection | 111 |
| November 1970 |
|
Nightfall and Other Stories | Fawcett Crest | Collection | 197 |
| 1971 |
|
Broedt daar een mens? | Bruna | Collection | 104 |
| June 1971 |
|
Urania #568 | Mondadori | MAGAZINE | 133 |
| October 1971 |
|
Nightfall Two | Panther / Granada | Collection | 35 |
| 1972 |
|
Futures Conditional | Bobbs-Merrill Company | Anthology | 5 |
| 1972 |
|
Nightfall Two | Panther | Collection | 35 |
| 1973 |
|
Nightfall Two | Panther | Collection | 35 |
| 1973 |
|
Great Science Fiction by Scientists | Collier Books | Anthology | 17 |
| April 1973 |
|
Der Todeskanal | Pabel | Collection | 134 |
| March 1974 |
|
L'amour, vous connaissez ? | Denoël | Collection | 111 |
| 1976 |
|
Nightfall Two | Panther / Granada | Collection | 35 |
| 1976 |
|
Nightfall Two | Panther | Collection | 35 |
| July 1977 |
|
Nightfall and Other Stories | Fawcett Crest | Collection | 197 |
| 1978 |
|
Great Science Fiction by Scientists | Collier Books | Anthology | 17 |
| 1978 | Nightfall Two | Panther / Granada | Collection | 35 | |
| April 1978 |
|
Sirius, #22 | Vjesnik | MAGAZINE | 129 |
| October 1978 |
|
Antologia Personale. Volume primo | Mondadori | Collection | 67 |
| November 1979 |
|
L'amour, vous connaissez ? | Denoël | Collection | 111 |
| 1981 |
|
Nightfall Two | Panther / Granada | Collection | 35 |
| November 1982 |
|
Der Todeskanal | Moewig | Collection | 135 |
| December 1984 |
|
Nightfall and Other Stories | Del Rey / Ballantine | Collection | 197 |
| 1985 |
|
Nightfall Two | Panther / Granada | Collection | 35 |
| November 1986 |
|
Magical Wishes | Signet / New American Library | Anthology | 166 |
| May 1987 |
|
Fantastic Stories: Tales of the Weird & Wondrous | TSR | Anthology | 174 |
| July 1987 |
|
Antologia Personale. Volume primo | Mondadori | Collection | 65 |
| November 1990 |
|
The Complete Stories, Volume 1 | Doubleday Foundation | Collection | 489 |
| November 1990 |
|
The Complete Stories, Volume 1 | Doubleday Foundation | Collection | 489 |
| March 1991 |
|
The Complete Stories, Volume 1 | Doubleday Foundation / SFBC | Collection | 489 |
| July 1991 |
|
Nightfall and Other Stories | Grafton / HarperCollinsPublishers | Collection | 253 |
| 1992 |
|
Cuentos completos I | Ediciones B | Collection | 557 |
| December 1992 |
|
Cuentos completos I | Ediciones B | Collection | 557 |
| March 1993 |
|
The Complete Stories, Volume 1 | HarperCollins (UK) | Collection | |
| January 1995 |
|
The Complete Stories: Volume Two | HarperCollins (UK) | Collection | 281 |
| 1997 |
|
The Complete Stories: Volume Two | Voyager | Collection | 281 |
| December 1997 |
|
Time Machines: The Greatest Time Travel Stories Ever Written | Carroll & Graf | Anthology | 279 |
| October 1998 |
|
I tempi che corrono | Mondadori | Anthology | 330 |
| August 2002 |
|
Time Machines: The Best Time Travel Stories Ever Written | Carroll & Graf | Anthology | 279 |
| September 2010 |
|
Cuentos completos I | Zeta | Collection | 651 |
| November 2013 |
|
The Time Traveller's Almanac | Head of Zeus | Anthology | 678 |
| March 2014 |
|
The Time Traveler's Almanac | Tor | Anthology | 678 |
| March 2014 |
|
The Time Traveler's Almanac | Tor | Anthology | 678 |
| August 2018 |
|
The Time Traveller's Almanac | Head of Zeus | Anthology | |
| July 2021 |
|
Nightfall and Other Stories | Del Rey | Collection | 205 |
| December 2021 |
|
The Time Traveller's Almanac | Apollo / Head of Zeus | Anthology | |
| November 2023 |
|
The Complete Stories: Volume Two | Harper Voyager (UK) | Collection | |281 |
| November 2024 |
|
Nightfall: And Other Stories | Harper Voyager (UK) | Collection | 257 |