Four guys -- a war hero, a wrestler, an underwater explorer, and a circus daredevil -- miraculously survive what should be a fatal plane crash. Declaring that they are now living on ''borrowed time,'' they decide to spend the rest of their lives fighting giant monsters, giant robots, giant criminals, giant aliens, and regular-size aliens with giant heads. ''If we have to die, let's not do it through boredom!'' The first ''Challengers'' cover shows one of the guys hammering a giant egg with a big monster hand busting out of it. That pretty much sums it up. They have no superpowers, but they do wear purple jumpsuits and will eventually live in a mountain.
This book reprints the first six appearances of the ''Challengers of the Unknown'' (Jan. 1957 -- July 1958), all beautifully drawn by the late, great Jack Kirby, with the first four written by Dave Wood. They're not quite as, well, fantastic as The Fantastic Four, which Stan Lee and Kirby would go on to create in 1961, but ''Challengers'' is fun, sincere, charming, and, given what most mainstream comics are like these days, a breath of fresh air. They really don't make 'em like this anymore.