First published in "Playboy", Jan '68
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| January 1972 |
|
Report on Planet Three and Other Speculations | Harper & Row | Nonfiction | 93 |
| 1973 |
|
Report on Planet Three and Other Speculations | Corgi Books / Transworld Publishers | Nonfiction | 100 |
| 1975 |
|
Report on Planet Three and Other Speculations | Corgi | Nonfiction | 100 |
| June 1982 |
|
Report on Planet Three and Other Speculations | Signet / New American Library | Nonfiction | 89 |
| 1984 |
|
Report on Planet Three and Other Speculations | Pan Books | Nonfiction | 100 |
| March 1985 | Report on Planet Three and Other Speculations | Berkley Books | Nonfiction | 91 | |
| July 1993 |
|
By Space Possessed: Essays on the Exploration of Space | Gollancz | Nonfiction | 125 |