Memento Mori by Muriel Spark

Audiobook.  A wonderfully fun book to listen to.  A group of folks in their 70s and 80s begin to receive anonymous phone calls reminding them they will die.  Some shrug off the news; others are terrified.  But mostly we hear about their many foibles, including affairs which began in 1907, blackmailing schemes, plots by companion/servants to inherit.  One old fellow has been recording detailed physical information about the elderly for 10 years and for the sake of his research, sends letters telling people of terrible news and asking them to take their pulse and temperature immediately upon hearing the news.  One character, Miss Taylor, perhaps the only sensible one, was in a public nursing home and we hear about the lives of the other women, all called Granny by the tyrannical nursing staff.  Miss Burstead, the ward supervisor, does get her much deserved comeuppance.