Norman Perrin defines redaction criticism as "the study of the theological motivation of an author as it is revealed in the collection, arrangement, editing, and modification of traditional material, and in the composition of new material ... redaction criticism directs us to the author as editor." Redaction criticism developed after World War II in Germany and arrived in England and North America by the 1950s. It focuses on discovering how and why the literary units were originally edited—"redacted"—into their final forms.