Margaret Cavendish, Duchess of Newcastle, published a wide variety of works including poems, plays, letters and treatises of natural philosophy, but her significance as a political writer has only recently been recognised. This major contribution to the series of Cambridge Texts includes the first ever modern edition of her Divers Orations on English social and political life, together with a new student-friendly rendition of her imaginary voyage, A New World called the Blazing World. Susan James explains the allusions made in this classic text, and directs readers to the many intellectual debates with which Cavendish engages. Together these two works reveal the character and scope of Margaret Cavendish’s political thought. She emerges as a singular and probing writer, who simultaneously upholds a conservative social and political order and destabilises it through her critical and unresolved observations about natural philosophy, scientific institutions, religion, and the relations between men and women.