Shari Lapena, born in 1960, published her first novel, Things Go Flying, in 2008 at the age of 48. Since then, she has published nine more novels, including her most famous novel, The Couple Next Door (2016), which is an international bestseller. According to her website, she started her career as an English teacher and lawyer and now writes full time while living in Ontario (“About.” Shari Lapena).

The Couple Next Door brought Lapena fame, as it has sold over four million copies worldwide and was the number one selling adult fiction book in the United Kingdom, along with being named “Book of the Year” by WHSmith. As her first thriller, the novel led Lapena to stay in that genre with each of her subsequent novels. She is praised for her ability to build suspense and create mystery while exploring difficult topics like trauma, the effect of keeping secrets, and physical and emotional abuse.

In What Have You Done?, Lapena builds suspense surrounding the murder of Diana. She presents three possible suspects—Cameron, Joe, and Brad—and then slowly reveals aspects of their lives that make their guilt even more likely. With Cameron, he repeatedly lies to the police, immaturely trying to protect his self-image at the expense of incriminating himself.