The Worst Witch
The Worst Witch is a series of children's books written and illustrated by Jill Murphy. The series are primarily boarding school and fantasy stories, with eight books already published. The first one, "The Worst Witch", was published in 1974 by Allison & Busby, and the most recent one, "First Prize for the Worst Witch", was published in 2018 by Puffin Books, the current publisher of all the series. The books have become some of the most successful titles on the Young Puffin paperback list and have sold more than 4 million copies.
Andre Norton
She wrote more than a dozen speculative fiction series, but her longest, and longest-running project was "Witch World", which began with the novel "Witch World" in 1963. The first six novels were Ace Books paperback originals published from 1963 to 1968. From the 1970s most of the series was published in hardcover editions. From the 1980s some were written by Norton and a co-author, and others were anthologies of short fiction for which she was editor. (Witch World became a shared universe). There were dozens of books in all.