Gertrude Chandler Warner

The Aldens start a business producing birthday parties and find themselves investigating a series of robberies taking place during their parties.

Jessie wants her science fair project to make a difference. So when she gets the chance to test a local creek for pollution, she can't wait to get started. But when things start going wrong with her experiment, Jessie and her siblings don't just have an experiment to investigate, they have a mystery to solve!

While staying at the Crooked House, the family home of their housekeeper Mrs. McGregor, the Aldens try to solve a riddle that will lead them to a hidden treasure.

Four orphans take shelter in an old boxcar during a storm, and, determined to make it their own, they turn it into a safe, cozy home.

The Aldens are excited to meet their favorite celebrity�Walter the Cat, who makes the funniest videos on the Internet! And when this celebrity cat inherits a million dollars from his owner, he becomes even more famous! But someone seems to be angry about the will and is stealing things from Walter�s house. Is this cat too famous for his own good?

"The Aldens find a hidden time capsule! Inside is a journal with clues to a treasure hunt. Who wrote the journal? And after a hundred years, can the Boxcar Children find the treasure?"--Back cover.

The Aldens help out at a medieval fair and try to find a valuable sword which has been stolen from the fair.

While visiting a recent purchase of Grandfather's, a ghost town in the Rocky Mountains, the Aldens encounter a mystery involving a run-down motel and a woman who may be a ghost.

When the children uncover a strange puzzle in a friend's back yard, it's the start of a "spy game" leading to gold. But first they must make sense of an old photo and a riddle, and learn just who is behind this mystery within a mystery.