The Medford Public Library welcomes historian Daniel A. Gagnon to discuss his recent biography of Salem Witch Trials victim Rebecca Nurse, Historian Daniel A. Gagnon will discuss his recent biography of Salem Witch Trials victim Rebecca Nurse, “A Salem Witch: The Trial, Execution, and Exoneration of Rebecca Nurse.” Gagnon will take questions from the audience following the presentation, and his book will be available for purchase.