| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| 1951 |
|
Empire | World Editions, Inc. | Novel | |
| February 2009 | Empire | Project Gutenberg | Novel | ||
| July 2010 |
|
Empire | Bottom of the Hill Publishing | Novel | |
| July 2010 |
|
Startling Stories, Summer 2010 | Wild Cat Books | Anthology | 4 |
| October 2010 |
|
Empire: With Hellhounds of the Cosmos! | Resurrected Press | Omnibus | |
| October 2010 |
|
Empire: With Hellhounds of the Cosmos! | Resurrected Press | Omnibus | |2 |
| January 2011 |
|
Empire | Benediction Classics | Novel | |
| January 2012 |
|
Empire | LibriVox | Novel | 7 |
| June 2012 |
|
Empire | CreateSpace | Novel | |
| September 2013 |
|
Empire | Gateway / Orion | Novel | |
| June 2014 |
|
The Fourth Golden Age of Science Fiction Megapack: Clifford D. Simak | Wildside Press | Omnibus | |
| September 2015 |
|
The Country Beyond the Curve / Empire | Armchair Fiction | Anthology | |2 |
| January 2016 |
|
Empire | Positronic Publishing | Novel | |
| February 2016 |
|
The Science Fiction Novel Super Pack #1 | Positronic Publishing | Anthology | |1 |
| March 2016 |
|
Empire | Start Publishing | Novel | |
| March 2016 |
|
The Science Fiction Novel Super Pack #1 | Start Publishing | Anthology | |1 |
| February 2020 |
|
Empire | e-artnow | Novel | |
| February 2020 |
|
Empire | Sharp Ink | Novel | |
| April 2020 |
|
Empire | Otbebookpublishing | Novel | |
| November 2022 |
|
Empire | DigiCat | Novel | |
| May 2024 |
|
Empire | HardPress Publishing | Novel |