Sparkling Cyanide
Sparkling Cyanide is a work of detective fiction by British writer  Agatha Christie, first published in the US by Dodd, Mead and Company in February 1945 under the title of Remembered Death and in UK by the Collins Crime Club in the December of the same year under Christie's original title. The US edition retailed at $2.00 and the UK edition at eight shillings and sixpence (8/6).The novel features the recurring character of Colonel Race for his last appearance to solve the mysterious deaths of 
a married couple, exactly one year apart. The plot of this novel expands the plot of a short story, "Yellow Iris".

Plot summary
One year earlier, seven people sat down to dinner at the Luxembourg restaurant. One, Rosemary Barton, never got up; instead she collapsed and died. The coroner ruled her death suicide by poisoning, due to post-flu depression. However, each of the guests had reason to want her dead:

Iris, Rosemary's sister, had recently learned that she was the sole beneficiary of her sister's will.
George, Rosemary's husband, had discovered her love letter to another man and her plans to leave her marriage.
Anthony Browne was a friend of Rosemary who she had accidentally discovered had served time in prison. He was also briefly infatuated with her before becoming attracted to Iris.
Stephen Farraday had had an affair with Rosemary, but later grew to resent her attachment to him and feared she would destroy his career and his marriage.
Sandra, Stephen's wife, had learned of the affair and worried her husband would leave her for Rosemary.
Ruth Lessing, George's secretary, would have been free to marry him with his wife out of the way. She secretly hated Rosemary.After Rosemary's death, her aunt Lucilla Drake moves in with George and Iris. She shows blind loyalty to her son, Victor, who is constantly requesting money from the family. Anthony returns to town from travel and forms a friendship with Iris. Six months later, George receives anonymous letters saying that Rosemary was murdered. George investigates and decides to repeat the dinner at the same restaurant, with the same guests, plus an actress who looks like his late wife, and who is meant to arrive late and startle the murderer into making a confession. A few days after the one-year anniversary of Rosemary's death, the dinner is held, ostensibly to celebrate Iris's eighteenth birthday. The actress does not arrive and George dies at the table – poisoned, like his wife, by cyanide in his champagne. His death might have been judged as suicide, but George shared his concerns and some of his plan with his friend Colonel Race.
Stephen is interrogated by the police, who suspect him of the two murders. However, Colonel Race suspects that Anthony killed Rosemary to silence her and is now pursuing Iris for her wealth, inherited from Rosemary. However, upon meeting him he realizes Anthony is not a criminal at all, but is really an agent for MI5. Iris confesses to Anthony that after George's death, she discovered cyanide in her purse, making it appear that the murderer was attempting to frame her.
After more investigating, Race incorrectly presumes the murderer to be Iris, but Anthony (after a trick with Race’s, Anthony’s and Chief Inspector Kemp’s drinks) has figured it all out.
Anthony realizes that Iris was the intended victim, not George, and Ruth was conspiring with Victor Drake (who she hoped to marry) to ensure he would inherit the family money. After the entertainment, George proposed a toast to Iris, when all sip champagne except her. When the group left the table to dance, Iris dropped her bag; a young waiter, retrieving it, misplaces it at the seat adjacent to hers. When, in the dark, the group returned to the table, Iris sat next to her original seat because of the misplaced bag. Everyone else therefore sat one seat away from where they were. George sat at Iris's original seat and drank the poisoned champagne. The anonymous letters to George were sent by Ruth, who then encouraged him to re-stage the dinner at the Luxembourg so that Victor and Ruth could kill Iris, as they killed Rosemary. To support a decision of suicide, Ruth had planted a packet of cyanide in Iris's bag, which packet dropped to the floor when she pulled her handkerchief out, without touching it (no fingerprints on it). Victor acted as a waiter, to drop the poison in the champagne during the show.
When this plot fails, Ruth attempts to run Iris over with a car, which the latter shrugs off as an accident. Colonel Race, together with the police and Anthony, unravel the truth in time to save Iris from Ruth. Her last attempt at killing Iris is to knock her unconscious in her bedroom, then turn on the fireplace gas, and leave the house. Anthony and Colonel Race break into Iris's room in the nick of time and revive her.
Victor is taken at New York at the request of the police and Ruth is caught as well. The case solved, the Farradays reaffirm their love for each other and Iris and Anthony make plans to marry.

Characters
Rosemary Barton: Wife of George Barton, who inherited wealth from her godfather. She was killed one year before this story.
George Barton: Rosemary's husband, fifteen years her senior.
Colonel Race: Investigator and friend of George Barton.
Iris Marle: Teenaged sister of Rosemary, set to inherit her wealth when she marries or turns twenty-one.
Anthony Browne: Boyfriend of Iris, who works to solve the many attempts to kill her.
Stephen Farraday: Rising member of parliament who had had a brief but passionate affair with Rosemary.
Alexandra "Sandra" Farraday: Stephen's wife, who before her marriage was the least-favored daughter of a prestigious noble family.
Lucilla Drake: Aunt to Rosemary and Iris, who inherits if Iris dies childless and unmarried.
Victor Drake: Son of Lucilla Drake, a man with desire to get money without work.
Ruth Lessing: Secretary to George. Note that Christie used a pun for this ruthless female conspirator.
Chloe West: Actress hired by George who bears a passing resemblance to Rosemary.

Short story and novel development and comparison
The plot of this novel is an expansion of a Hercule Poirot short story entitled "Yellow Iris," which had previously been published in issue 559 of the Strand Magazine in July 1937 and in book form in The Regatta Mystery and Other Stories in the US in 1939. It was published in book form in the UK in Problem at Pollensa Bay in 1991.
The full-length novel has Colonel Race as the central investigative character in place of Poirot, who had that role in the short story. The novel uses the basics of the short story, including the method of the poisoning, but changes the identity of the culprit(s) – not for the first time, when Christie rewrote her own work.

Literary significance and reception
The book was not reviewed in The Times Literary Supplement.
Maurice Richardson, in the 13 January 1946 issue of The Observer wrote, "Agatha Christie readers are divided into two groups: first, fans like me who will put up with any amount of bamboozling for the sake of the pricking suspense, the close finish, six abreast, of the suspect race, and the crashing chord of the trick solution; second, knockers who complain it isn't cricket and anyway there's nothing to it. Fans, I guarantee will be quite happy with Sparkling Cyanide, a high income group double murder, first of wayward smarty Rosemary, second of dull husband George at his lunatic reconstruction-of-the-crime party. It  is too forced to rank with her best Number One form, but the suspect race is up to scratch and readability is high. Making allowances for six years of spam and cataclysm, quite a credible performance."An unnamed reviewer in the Toronto Daily Star of 24 February 1945 said, "Suspense is well maintained and suspicion well divided. While this mystery lacks Hercule Poirot, it should nevertheless please all Agatha Christie fans, especially those who like the murders in the fast, sophisticated set."Robert Barnard: "Murder in the past, previously accepted as suicide. Upper-class tart gets her come-uppance in smart London restaurant, and husband later suffers the same fate. Compulsively told, the strategies of deception smart as a new pin, and generally well up to 'forties standard. But the solution takes more swallowing than cyanided champagne."

Adaptations
TV
In 1983, CBS writers Robert Malcolm Young, Sue Grafton and Steven Humphrey adapted the book into a television film, directed by Robert Michael Lewis, set in modern day California and starring Anthony Andrews as the central character, Tony Browne, with Deborah Raffin as Iris Murdoch, Pamela Bellwood as Ruth Lessing, Josef Sommer as George Barton, David Huffman and June Chadwick as Stephen and Sandra Farraday, Nancy Marchand as Lucilla Drake, and Christine Belford as Rosemary Barton. This adaptation did not feature Colonel Race.In 1993, the short story that served as the basis for this novel, The Yellow Iris, was adapted for television by Anthony Horowitz and directed by Peter Barber-Fleming  in an episode of the ITV series Agatha Christie's Poirot starring David Suchet.
In late 2003, it was loosely adapted by Laura Lamson for ITV1, again in a modern setting, and involving a football manager's wife's murder. In this adaptation Colonel Race was renamed Colonel Geoffrey Reece, and given a partner, his wife, Dr. Catherine Kendall. The byplay between Reece (played by Oliver Ford Davies) and Kendall (played by Pauline Collins) was somewhat similar to Christie's characters Tommy and Tuppence.
In 2013, it was adapted as an episode of the French television series Les Petits Meurtres d'Agatha Christie.

Radio
In 2012, a three-part adaptation by Joy Wilkinson was broadcast on BBC Radio 4 directed by Mary Peate, with Naomi Frederick as Iris, Amanda Drew as Ruth, Colin Tierney as Anthony, James Lailey as Stephen, Sean Baker as Colonel Race and Jasmine Hyde as Rosemary.

Publication history
1945, Dodd Mead and Company (New York), February 1945, Hardback, 209 pp
1945, Collins Crime Club (London), December 1945, Hardback, 160 pp
1947, Pocket Books (New York), Paperback (Pocket number 451)
1955, Pan Books, Paperback, 159 pp (Pan number 345)
1955, Pan Books, Paperback, (Great Pan 156)
1960, Fontana Books (Imprint of HarperCollins), Paperback, 160 pp
1978, Ulverscroft Large-print Edition, Hardcover, 358 pp; ISBN 0-7089-0223-5
2010, HarperCollins; Facsimile edition, Hardcover: 160 pages; ISBN 978-0-00-735470-2The novel's first true publication was the serialisation in The Saturday Evening Post in eight instalments from 15 July (Volume 216, Number 3) to 2 September 1944 (Volume 217, Number 10) under the title Remembered Death with illustrations by Hy Rubin.
The novel was first serialised, heavily abridged, in the UK in the Daily Express starting on Monday, 9 July 1945 and running for eighteen instalments until Saturday, 28 July 1945. The first instalment carried an uncredited illustration.

References
External links
Sparkling Cyanide at the official Agatha Christie website
Sparkling Cyanide (1983) at IMDb
Sparkling Cyanide (2003) at IMDb