Although Thomas Cranmer was a key participant in the changes to English life brought about by the Reformation, his reticent nature and lack of extensive personal writings have left a vacuum that in the past has too often been filled by scholarly prejudice or presumption. This volume examines little used manuscript sources to reconstruct Cranmer's theological development on the crucial Protestant doctrine of justification. Ashley Null explores Cranmer's cultural heritage, why he would have been attracted to Luther's thought, and then provides convincing evidence for the Reformed Protestant Augustinianism which Cranmer enshrined in the formularies of the Church of England.