ImI'm looking for the title and author of a book (possibly from the 60s or 70s) where the world is on the brink of nuclear war and aliens abduct people from around the globe and put them in suspended animation.
They are then woken up in small groups at intervals of time to be sent back to Earth to see if it is safe to live. The first groups die from radiation sickness, but the last group survivesurvives and find other survivors (in Antarctica I think).
They then group together to defeat the aliens.