AUTHOR'S PERSONAL INFLUENCE:
Agatha Christie was born in Devon, England (where the story takes place). She also had experience during World War 1 when she worked in a hospital. Later on in World War 2 she served again, but this time as pharmacist. Both of these opportunities provided the chance to learn about medicines and poisons (which she uses quite frequently in the novel) and to experience traumatizing events that could have influenced her writings.