Sparkling Cyanide

It's been less than a year since beautiful heiress Rosemary Barton took her own life during a birthday dinner in her honor. Her husband George never believed that his fun-loving wife would commit suicide--especially now that he's received two anonymous letters that suggest cold-blooded murder. One implicates even George himself. It's true he long suffered Rosemary's infidelities. But what about her embittered sister who was left out of the family will? Or any of Rosemary's secret lovers, not to mention their betrayed wives? Now one of them has ever forgotten Rosemary. Nor has any one of them ever forgiven her. But only one of them killed her...
"So skillfully has Agatha Christie told the story that the denouement will come as a surprise to nine readers out of ten." -The New York Times