"You Should Have Known" is a psychological thriller novel by Jean Hanff Korelitz. The story follows Grace Sachs, a successful therapist who is shocked when her husband, Jonathan, goes missing. As she navigates the aftermath, Grace uncovers secrets about her marriage and the people around her, leading to a gripping exploration of trust and betrayal. The novel delves into themes of perception and the complexities of relationships. It raises questions about how well we truly know those closest to us and the consequences of ignoring red flags. The narrative builds tension as Grace seeks the truth behind her husband's disappearance.