The book "The Third Window" was written by the American writer Anne Douglas Sedgwick. This is an exciting detective story that unfolds in an old mansion with a secret in every corner. The main character, a young teacher Lillian Ross, decides to solve a crime that happened in this house a century ago. She begins an investigation, where each new crime leads to secrets of the past, which become the key to solving mysterious disappearances. "The Third Window" is a dizzying mixture of mystery, tension and unexpected turns of events that keep the reader in suspense until the last page.