On the Beach by Nevil Shute
A war no one fully understands has devastated the planet with radioactive fallout from massive cobalt bombing. Melbourne, Australia, is the only area whose citizens have not yet succumbed to the contamination. But there isn’t much time left, a few months, maybe more—and the citizens of Melbourne must decide how they will live the remaining weeks of their lives, and how they will face a hopeless future.
Published in 1957, On the Beach is considered a classic nuclear holocaust novel, and a masterpiece of speculative fiction.