First off, let me say that this copy, which I got for under a dollar from The Paperback Rack, is the proud winner of Worst Cover Yet. Click on that thing and really check it out. It's like they summarized the plot for a seven year old, gave her glue and round-end scissors, and said, "do it up, kid."
Just had to say that, because it's sort of been bugging me.
With that out of the way, I did enjoy the book. It's a quick read, fairly slim, but nice and creepy in that nuclear-war-leading-to-the-complete-loss-of-human-life 1950s way. It's interesting in that the enemy isn't the Soviets (or even us, from their point of view), but the nuclear arms themselves. A 2 hour war is set off by a glitch in the system, and it wipes us out from top to bottom.
The whole thing is done diary-style, by a military man living 7 levels below the earth, where he should be among the safest people on the planet. His daily life, food, air, and social needs are met without worry. He has only to do his duty and stand the fact that he'll never be above ground again. It's the loss of sunshine, more than anything, that preys on him. You know, I suffer from a fear of being trapped underground, and I could feel the weight of all that rock and soil the whole time I was reading.
The style was a little dated, but what do you expect? It was written 50 years ago. My main complaint has to be the sexism that permeated the narrative. The main female character, although a psychiatrist and one of the chosen few living in the deepest, safest level, giggles and flirts and generally acts like a manipulative female stereotype. Frankly, even Heinlein does a better job writing women, and that ain't saying much.
final thought: Worth reading, but more as a blast from the past than a warning for now.