The novel "Elephants Can Remember" has a subplot in the fading memories of its aged characters. By the time Agatha Christie wrote the novel, Christie herself was suffering from memory problems. A 2009 study suggested that Christie had actually lost much of the vocabulary which she had used in earlier novels, and concluded that she was likely suffering from some form of late-onset dementia, perhaps Alzheimer's disease.
In the novel, the investigation is entirely concerned with the deaths of General Alistair Ravenscroft, his wife Margaret Ravenscroft, and his sister-in-law Dorothea, which all occurred 14 years before the present. The adaptation also adds a present day murder and two murder attempts which are mysteriously connected to the older case.
"Elephants Can Remember" was the seventh and last Christie novel to feature the character of Ariadne Oliver. Oliver had previously appeared in "Cards on the Table" (1936), "Mrs McGinty's Dead" (1952), "Dead Man's Folly" (1956), "The Pale Horse" (1961), "Third Girl" (1966), and "Hallowe'en Party" (1969).
The novel "Elephants Can Remember" featured the recurring character Superintendent Spence in retirement, who is replaced by Detective Inspector Beale in the adaptation. Spence had previously appeared in the novels "Taken at the Flood" (1948), "Mrs McGinty's Dead" (1952), and "Hallowe'en Party" (1969).
"Elephants Can Remember" (1972) was the 32nd Hercule Poirot novel published by Agatha Christie, and the last actually written during her life. The 33rd Poirot novel, "Curtain" (1975), was written c. 1940 but only published at the end of Christie's literary career.