Shannara is a series of high fantasy novels written by Terry Brooks, beginning with The Sword of Shannara in 1977 and concluding with The Last Druid which was released in October 2020; there is also a prequel, First King of Shannara. The series blends magic and primitive technology and is set in the Four Lands, which are identified as Earth long after civilization was destroyed in a chemical and nuclear holocaust called the Great Wars. By the time of the prequel First King of Shannara, the world had reverted to a pre-industrial state and magic had re-emerged to supplement science. Setting.
https://en.wikipedia.org/wiki/Shannara