The Clue is a detective story by American author Carolyn Wells.

This is the first novel featuring the Sherlock Holmes like detective Fleming Stone who is brought in to solve another mystery.

Once Carolyn Wells began, or re-invented her writing career, 'The Clue' was her initial book which strayed from children's writings into mysteries and detective stories. It is also in this book we are introduced to her most famous of detectives, Fleming Stone.

On the eve of her wedding day, Madeleine Van Norman, a beautiful young lady who is soon to come into her family fortune is found dead, apparently stabbed with an ominous blood-stained letter opener found nearby. There is nobody within the household who is not considered a suspect by the police, but how could a killer have slipped through the doors of Madeleine’s locked bedroom?

It must have been suicide, as a note was found lying on a table near her body. Or was it? An intriguing mystery ensues which hinges on the discovery of a single, all-important clue.

The Clue was first published in 1909. Audiobook read by Roger Melin, running time 7 hours, 58 min. Unabridged full version. Also available as E-Book: ePUB, 63,300 words, average reading time 5 hours, 15 min.

Carolyn Wells (1862–1942) was an American author and poet. Carolyn Wells wrote a total of more than 170 books. During the first ten years of her career, she concentrated on poetry, humor, and children's books. However, Carolyn Wells began reading mystery stories written by Anna Katherine Green, and from then on she devoted her writings to puzzling mysteries in a similar vein.