Title: An introduction to philosophy
First published: 1925
Description: Mark and Billy stumble upon a coded message in a bottle that has been washed up on the beach. They decipher the code and learn that Tom, who lives on a nearby island, wants to start a secret club. They form the Secret Three and have many startling adventures together.
Subjects: Philosophy, Introductions, Philosophie, Ocean bottles, Juvenile fiction, Friendship, Code and cipher stories, Clubs, Fiction, Ciphers