Marjorie Weinman Sharmat

THE OWL EXPRESS
Nate, the great detective, and his dog Sludge, hit the rails on their latest case. Their mission: To guard an owl named Hoot. Hoot belongs to Nate’s cousin, Olivia Sharp, and she thinks someone on the train might be out to get her feathered friend. Then Hoot disappears! 
THE TARDY TORTOISE
The sun is shining, the birds are singing, and someone is eating the flowers in Nate's garden. A green tortoise is slowly stepping...

As more and more of his flowers display the bite marks of a wandering tortoise, Nate sets out to uncover the mystery of the reptile's origins.

Irving Morris Bear who loves to eat learns an important lesson about Thanksgiving from his friends.

Nate the Great finds mystery at the beach when Oliver's beach bag vanishes.

Nate the Great investigates two cases that may be connected, involving a missing valentine and a valentine that came from nowhere.

The reader is asked to help Nate the Great solve the mystery of his friend Annie's missing dog Fang.

Nate the Great, the junior sleuth, and his faithful dog, Sludge, track down a friend's missing stamp, the one with the picture of a dinosaur.

While traveling on the train to San Francisco with his cousin Olivia's owl, Nate the Great and his dog Sludge must use all of their detective skills when the owl suddenly disappears.