Now in one amazing volume collecting SHOWCASE 6, 7, 11 and 12 and CHALLENGERS OF THE UNKNOWN #1-8, these are the original 1950s tales of four death defying adventurers and their incredible exploits.
- ISBN13 9781401234744
- Publish Date 3 July 2012 (first published 22 June 2012)
- Publish Status Out of Print
- Out of Print 14 October 2016
- Publish Country US
- Imprint DC Comics
- Format Hardcover
- Pages 320
- Language English