The Secret Adversary is a work of detective fiction by Agatha Christie. Upon publication of the first book edition it was reviewed by The Times Literary Supplement in its edition of January 26, 1922 which described it as "a whirl of thrilling adventures". It stated that the characters of Tommy and Tuppence as "refreshingly original" and praised the fact that the "identity of the arch-criminal, the elusive "Mr Brown", is cleverly concealed to the very end". The New York Times Book Review was also impressed, stating, "It is safe to assert that unless the reader peers into the last chapter or so of the tale, he will not know who this secret adversary is until the author chooses to reveal him." "Miss Christie has a clever prattling style that shifts easily into amusing dialogue and so aids the pleasure of the reader as he tears along with Tommy and Tuppence on the trail of the mysterious Mr. Brown. Miss Christie manages to invest them with a new sense of individuality that renders them rather absorbing."