Mary Sidney Herbert, Countess of Pembroke, provides a uniquely interesting case study of the ways in which a range of editorial theories, practices and assumptions about potential readerships have been applied to an early modern woman writer. Very little attention has been paid to the circulation and reception of the Sidney Psalter prior to the twentieth-century. This chapter traces the ways in which the Psalter was represented and mediated and explores the significance of these to some of the key critical paradigms structuring the intepretation of this work – questions of gender, aesthetic value, influence and collaboration.