Gertrude Chandler Warner

When the Alden children accompany their grandfather on a trip to Seattle, they discover clues throughout the city, seemingly planted just for them.

When they take their dog, Watch, for obedience training, the Alden children discover that some of the dogs in the class have vanished and decide to try to solve the mystery of their disappearance.

While visiting a friend of their grandfather's on Sullivan's Island, off the coast of South Carolina near Charleston, the Boxcar Children encounter mysterious activities related to rumors of a buried pirate treasure.

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.

While helping run Jerry Taylor's general store, the Alden children investigate his mysterious employee Nancy.

"The Aldens visit the shore in New Jersey and help out at an amusement pier that is rumored to be unsafe"--

The Aldens travel to Ireland to explore castles. While visiting Duncarraig Castle the children discover a cloaked figure roaming around.

"The Aldens are on a special vacation up north to see the Calgary Stampede -- a cowboy celebration of Canada's frontier spirit! There's a parade through the streets of Calgary, a spectacular stage show, and plenty of fun things to do. But behind the scenes at the festival, an important piece of jewelry goes missing. Can the Boxcar Children find the thief before the big show is ruined?"--Jacket flap.

While visiting an old mansion, the Aldens investigate the possibility that it may be haunted.

"A mystery surrounds the old yellow house on Surprise Island! Years ago, a man vanished from the house, and no one knows how or why. Now a long-lost clue leads the Aldens to investigate the mystery -- and to a new adventure!" -- Publisher's description