The Mysterious Affair at Styles is Agatha Christie’s debut novel, published in 1920, and it marks the first appearance of Hercule Poirot, her iconic detective. The story is set during World War I at Styles Court, a sprawling manor in the English countryside. When the wealthy widow Emily Inglethorp is poisoned, her household is thrown into turmoil, and suspicion falls on various family members and associates, each with their own motives.

The novel is narrated by Captain Arthur Hastings, a friend of Poirot’s, who is recuperating from war injuries at Styles. When Mrs. Inglethorp is murdered, Hastings calls on Poirot, who happens to be living nearby as a refugee from Belgium. With his ‘little grey cells’ and trademark eccentricities, Poirot meticulously examines clues, alibis, and psychological nuances to uncover the truth.

Christie wrote The Mysterious Affair at Styles as a response to a challenge from her sister, who dared her to write a detective story. The novel introduces many elements that would become trademarks of her work, including complex plotting, red herrings, and the famous ‘gathering of suspects’ scene, where Poirot reveals the killer.

The book was well-received and helped set the stage for Christie’s prolific career, laying the groundwork for the Golden Age of Detective Fiction. It remains a classic in the genre and a testament to Christie’s storytelling skill and ingenuity.