Two covers of the novel "Vault of the Ages" (1952) by Poul Anderson,
500 years in the future after a nuclear holocaust, there is Carl, a young man the son of the Chief of the Dalesmen, a community of peaceful farmers. This community is threatened by the Lann, a tribe of warriors from the north who are fleeing their increasingly cold homeland. On their way they are conquering and subjugating all other communities. Looking for help, Carl enters the ruins of one of America's ancient cities, which are inhabited by ragtag groups of people whom everybody calls witchmen or worse.
All in all a good old post-apocalyptic action novel, where people has fallen back on a kind of sword and sorcery.
11 hours ago