"The First Duke and Duchess of Newcastle-upon-Tyne" by Thomas Longueville is a historical account written in the early 20th century. The book chronicles the lives and times of William Cavendish, the first Duke of Newcastle, and his wife, Margaret, who was a notable writer and poet of the 17th century. It delves into their remarkable biographies against the backdrop of the tumultuous political landscape of their era, including the English Civil War and the struggles surrounding the monarchy. The opening of this work sets the scene by establishing the author’s intent to illuminate the lives of the first Duke and Duchess of Newcastle while inviting readers to explore historical documents and manuscripts that shed light on their experiences. Longueville introduces readers to the early life of William Cavendish and highlights the significance of his influential family background. The text touches on the Duke's progression through the ranks of nobility, his political aspirations, and his relationship with renowned figures of the time, paving the way for a deeper exploration of their legacies as rulers, influencers, and patrons in a transformative period of English history. (This is an automatically generated summary.)