Although Marguerite de Navarre's unique position in sixteenth-century France has long been acknowledged and she is one of the most studied women of the time, until now no study has focused attention on Marguerite's political life. Barbara Stephenson here fills the gap, delineating Marguerite's formal political position and highlighting her actions as a figure with the opportunity to exercise power through both official and unofficial channels. Through Marguerite's surviving correspondence, Stephenson traces the various networks through which this French noblewoman exercised the power available to her to further the careers of political and religious clients, as well as her struggle to protect the interests of her brother the king and those of her own family and household. The analysis of Marguerite's activities sheds light on noble society as a whole.