At last, DC collects Jack Kirby's run of adventure epics from SHOWCASE #6, 7, 11 and 12 and CHALLENGERS OF THE UNKNOWN #1-8 in a single paperback volume! These are the tales that introduced Ace Morgan, Red Ryan, Rocky Davis and Professor Haley-four men living on borrowed time, determined to face-and overcome-adversity in the form of monsters, aliens and would-be world conquerors!