Siege of the Unseen / The World Swappers
| First published | 1959 |
|---|---|
| Publisher | Ace Books |
| Format | dos |
| Type | Omnibus |
| Catalog ID | D-391 |
| Cover art | Ed Valigursky |
| Pages | 103+153 |
| Price | $0.35 |
- Cover for Siege of the Unseen has "Complete Novel"; 103 pages
- Cover for The World Swappers has "First Book Publication"; 153 pages
- Cover art for both titles is not credited and there are no visible signatures. ACE Image Library credits Valigursky with Siege of the Unseen
- Month of publication from Jad Smith's John Brunner biography
| Page | Title | Author(s) | Type |
|---|---|---|---|
| 5 | Siege of the Unseen | A. E. van Vogt | Novella |
| 5 | The World Swappers | John Brunner | Novel |