After watching “Threads,” I’m interested in its literary equivalent(s). Recommendations?

Hello there, I just watched the completely harrowing "Threads" (1984) and I was wondering which post apocalyptic book(s) you'd consider to be just as harrowing – if not more so.

I'm looking for authors who can sketch out an apocalyptic scenario convincingly, with well-drawn characters grappling with a sudden scenario of massive proportions. Thanks immensely in advance.