The Gandalara cycle

Randall Garrett was an American science fiction and fantasy author. He was a prolific contributor to Astounding and other science fiction magazines of the 1950s and 1960s. Garrett is best known for the Lord Darcy books, the novel Too Many Magicians and two short story collections. He was also an inveterate punster (defining a pun as "the odor given off by a decaying mind"), he was a favorite guest at science fiction convention. Source: wikipedia