"The Long Secret" is a children's novel written by Louise Fitzhugh, published in 1965. It follows the adventures of Harriet the Spy, a young girl who is curious and observant. In this story, Harriet navigates the complexities of friendship and loyalty while uncovering secrets about her peers and herself. The plot centers around Harriet's relationship with her friends, particularly Sport, as they explore themes of trust and betrayal. As Harriet grapples with her own secrets, she learns valuable lessons about honesty and the impact of her actions on those around her.