The Girl on the Train is a psychological thriller written by Paula Hawkins. The story follows Rachel Watson, a woman who becomes entangled in a missing person investigation after witnessing something suspicious from her train window. As Rachel delves deeper into the mystery, she becomes increasingly unreliable as a narrator due to her struggles with alcoholism and memory loss. The Girl on the Train is a gripping and suspenseful novel that keeps readers on the edge of their seats. Hawkins' skillful storytelling and complex characters make this book a must-read for fans of psychological thrillers.