This novel is extension of novella "Adaptation".
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| 1967 |
|
Nebula Alert / The Rival Rigelians | Ace Books | Omnibus | 5|4 |
| March 1968 |
|
Urania #484 | Mondadori | MAGAZINE | 3 |
| June 1974 |
|
The Rival Rigelians and Planetary Agent X | Ace Books | Omnibus | 5|1 |
| 1975 |
|
Conflict in de Ruimte / Planetair Agent X | Scala | Omnibus | 3 |
| November 1980 |
|
Millemondinverno 1980: Tre Romanzi completi di Mack Reynolds | Mondadori | Omnibus | 293 |
| September 2011 |
|
The Rival Rigelians | Gateway / Orion | Novel | |
| June 2018 |
|
The Rival Rigelians | Wildside Press | Novel | |
| July 2020 |
|
The Rival Rigelians | Wildside Press | Novel |