"The Phantom of the Opera" is a gothic novel by Gaston Leroux. The story is set in the Paris Opera House and follows the mysterious Phantom, who is known to haunt the building's backstage and underground passages. The Phantom becomes infatuated with the opera singer Christine Daaé and starts to manipulate her career, using his musical genius to train her voice and arranging for her to take the lead role in productions.
As Christine's success grows, so does the Phantom's obsession, and he becomes increasingly controlling and dangerous. Meanwhile, Christine's childhood friend Raoul, who is now in love with her, becomes suspicious of the Phantom and begins to investigate his past.
As the story unfolds, the reader learns more about the Phantom's tragic history and the reasons behind his disfigurement and his desire for control over the Opera House. The novel culminates in a dramatic confrontation between the Phantom, Raoul, and Christine, which reveals the true nature of the Phantom's madness and his love for Christine.
Overall, "The Phantom of the Opera" is a gripping tale of love, obsession, and the dangers of unchecked power. It has inspired numerous adaptations in film, theater, and music, and has become a classic of gothic literature.