Gertrude Chandler Warner

The Pumpkin Head Mystery: Every fall at the Beckett farm, visitors come to buy pumpkins and go on hayrides. Best of all, Henry, Jessie, Violet, and Benny get to dress up in costumes and help with the fun. But something is haunting the farm . . . a mysterious ghost with a glowing pumpkin head! The...

The Aldens are helping the owner of a local restaurant grow delicious food in a garden. They work hard to water and weed and take care of the fruits and vegetables that are growing. But soon the children notice the strangest thing--the plants are moving.

...

One day in the park, the Aldens' dog, Watch, comes across a mysterious box with a note inside. "Congratulations!" the note says. "You've found it!" The box is part of a fun new treasure-hunting game.

...

The Aldens find a castaway on a South Sea island. How did he get there and who is he?

...