They are hired for a job that leads them both to many dangerous situations, meeting allies as well, including an American millionaire in search of his cousin.

In 1920 London, demobilised soldier Tommy Beresford reunites with his childhood friend and war volunteer Prudence "Tuppence" Cowley.

Tommy and Tuppence's investigation leads them to the home of Mrs Marguerite "Rita" Vandemeyer, a woman with several powerful friends, including Whittington and Sir James Peel Edgerton, K C. Under cover, Tuppence obtains a job as Mrs Vandemeyer's maid and enlists the help of a young boy working there named Albert.

Tuppence offers Vandemeyer a large bribe to tell the whereabouts of Jane Finn, but she screamed and fainted after seeing Hersheimmer and Edgerton.

He commits suicide using poison concealed in his ring, the compelling evidence to persuade Mr Carter of his old friend's guilt.

It stated that the characters of Tommy and Tuppence were "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 critic for The New York Times Book Review (11 June 1922) was also impressed: "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."

Nevertheless it conceded thatMiss 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.

Many of the situations are a bit moth-eaten from frequent usage by other writers, but at that Miss Christie manages to invest them with a new sense of individuality that renders them rather absorbing.

It tells how the dauntless pair foils a plot to foment labour unrest and red revolution in Britain, masterminded by the man behind the Bolshevists.

Made in Germany by the Orplid Film company, it was released in that country on 15 February 1929 as Die Abenteurer G.m.b.H., a silent movie which ran for 76 minutes.

Previously thought to be lost, it was given a rare showing at the National Film Theatre on 15 July 2001[8] The novel was adapted twice for television, in 1983 and in 2014 (aired July–August 2015 in the UK).

In February 2014, the BBC announced it had commissioned the TV series Partners in Crime, with three episodes as an adaptation of The Secret Adversary, written by Zinnie Harris.

[9] It is not set in the post-Great War period, so Tommy and Tuppence are not the young things of that era, are married and have a son sent off to school.

[citation needed] On 16 February 2016, Great Lakes Theater debuted a 70-minute stage adaptation as part of their educational programming.

[14] The dedication of the book reads: "To all those who lead monotonous lives in the hope that they experience at second hand the delights and dangers of adventure".

This statement was one of only two times that Christie addressed a dedication to her readers, the other occasion being the penultimate Tommy and Tuppence book, By the Pricking of My Thumbs in 1968.