Zilpha Keatley Snyder was an American author of books for children and young adults. Three of Snyder's works were named Newbery Honor books: The Egypt Game, The Headless Cupid and The Witches of Worm. She was most famous for writing adventure stories and fantasies.
Excerpt from Wikipedia, available under CC BY-SA 4.0.

The Headless Cupid
1971
ISBN 9780689206870
The Famous Stanley Kidnapping Case
2014
ISBN 9781481424707
Janie's Private Eyes
1990
ISBN 9780440402794
Gib Rides Home
2002
ISBN 9780786248568
Blair's Nightmare
2014
ISBN 9781481403214
Black and Blue Magic
1988
ISBN 9780440400530
Below the Root
1992
ISBN 9780440212669
Gib and the gray ghost
2000
ISBN 9780385326094
The Trespassers
1996
ISBN 9780440911487
The Changeling
1970
ISBN 9780689206108
The Witches of Worm
1972
ISBN 9781416990536
The Ghosts of Rathburn Park
2002
ISBN 9780385900645
Fool's Gold
2014
ISBN 9781480471504