"The Man in the Brown Suit" by Agatha Christie is a detective novel published in 1924. When Anne Beddingfeld witnesses a man's death at a London tube station, she picks up a mysterious note that launches her into a dangerous adventure. Following clues across continents to South Africa, Anne pursues the truth about murder, stolen diamonds, and a shadowy international criminal known only as "the Colonel." With danger at every turn, she must uncover the real identity of the elusive man in the brown suit.