The Secret Adversary

The Secret Adversary is a mystery novel by the English writer Agatha Christie, published in January 1922 and the second of her books to appear.

It introduces Tommy and Tuppence, who went on to feature in three further novels and a collection of short stories across the rest of Christie's career, and it makes them a different kind of pair from the detectives she was already writing: young, cheerful, broke and unprepared, with no authority behind them and nothing to fall back on except nerve. The story is set in London in 1920 and starts with a missing treaty, a missing woman and a man who is not what he says he is, and the plot keeps the identity of the criminal at its centre secret almost to the last chapter. What gives the book its period flavour is the texture around the mystery: the employment advertisements, the boarding houses, the returned soldiers looking for work and the American millionaire who is hunting for his cousin. Reviews at the time were generally warm, and the novel is the first indication of how comfortable Christie would be with a plot that runs on coincidence and conversation rather than physical evidence.