The book, Before I Go to Sleep belongs to the genre of thrillers. This book recounts the tale of a woman who wakes up one morning with a man next to her sleeping. She at first feels extremely ashamed of herself and tries to understand her situation and realizes that the man in the bed is her husband and she has lost two decades of her memory. What follows is her journey of reclaiming her life and identity from what she can gather through her journal entries in a diary and also tries to get through to the therapist who has been treating her from the day she suffered the accident which resulted in forgetting the events of the previous day every morning.