'The zeal and vigor with which Gregory defined and pursued reforming policies during...a period of revolution in Latin Christendom is not debatable. The large selection of letters translated by Ephraim Emerton puts at a reader's disposal the evidence of the papal documents themselves...Emerton's introduction is useful, both for setting Gregory into the framework of eleventh-century ecclesiastical reform, and for a diplomatic orientation to the Register and the survival of Gregory's correspondence.' -Robert Somerville, Columbia University